Science.gov

Sample records for global mass estimates

  1. Estimating global specific leaf area from MODIS leaf area index and model-simulated foliage mass

    NASA Astrophysics Data System (ADS)

    Baruah, P. J.; Yasuoka, Y.; Ito, A.; Dye, D.

    2006-12-01

    Specific leaf area (SLA) is an important leaf trait that is universally correlated positively to leaf nitrogen, leaf turnover rates, relative growth rate and most importantly, photosynthetic capacity. Though SLA is genetically encoded, it is often spatially variable within a species and within a single biome due to variable environmental conditions. However, without a global SLA map, global ecosystem models that use SLA, generally fix a single value for a particular biome. In this study, we develop a methodology to estimate global SLA from a remote sensing-derived key ecosystem variable, leaf area index and foliage mass estimated by a terrestrial ecosystem model SimCYCLE. SimCYCLE uses climatic inputs, land-cover data and biomass-allocation to estimate leaf biomass in a process-based scheme. Model-estimated foliage mass and MODIS leaf area index are assumed to represent the most-accurate ground condition to estimate SLA for the entire globe at 0.5 degree resolution. Validation of estimated specific leaf area is done with a published field-sampled global dataset, and additional field-sampled SLA data collected from published literatures. The validation data is also used for rectification of unrealistic values of estimated SLA to produce a global SLA map, which we strongly believe, would be valuable to improve estimates of carbon dynamic across individual biomes upon assimilation with the ecosystem models.

  2. Incorrect interpretation of carbon mass balance biases global vegetation fire emission estimates.

    PubMed

    Surawski, N C; Sullivan, A L; Roxburgh, S H; Meyer, C P Mick; Polglase, P J

    2016-01-01

    Vegetation fires are a complex phenomenon in the Earth system with many global impacts, including influences on global climate. Estimating carbon emissions from vegetation fires relies on a carbon mass balance technique that has evolved with two different interpretations. Databases of global vegetation fire emissions use an approach based on 'consumed biomass', which is an approximation to the biogeochemically correct 'burnt carbon' approach. Here we show that applying the 'consumed biomass' approach to global emissions from vegetation fires leads to annual overestimates of carbon emitted to the atmosphere by 4.0% or 100 Tg compared with the 'burnt carbon' approach. The required correction is significant and represents ∼9% of the net global forest carbon sink estimated annually. Vegetation fire emission studies should use the 'burnt carbon' approach to quantify and understand the role of this burnt carbon, which is not emitted to the atmosphere, as a sink enriched in carbon. PMID:27146785

  3. Incorrect interpretation of carbon mass balance biases global vegetation fire emission estimates

    NASA Astrophysics Data System (ADS)

    Surawski, N. C.; Sullivan, A. L.; Roxburgh, S. H.; Meyer, C. P. Mick; Polglase, P. J.

    2016-05-01

    Vegetation fires are a complex phenomenon in the Earth system with many global impacts, including influences on global climate. Estimating carbon emissions from vegetation fires relies on a carbon mass balance technique that has evolved with two different interpretations. Databases of global vegetation fire emissions use an approach based on `consumed biomass', which is an approximation to the biogeochemically correct `burnt carbon' approach. Here we show that applying the `consumed biomass' approach to global emissions from vegetation fires leads to annual overestimates of carbon emitted to the atmosphere by 4.0% or 100 Tg compared with the `burnt carbon' approach. The required correction is significant and represents ~9% of the net global forest carbon sink estimated annually. Vegetation fire emission studies should use the `burnt carbon' approach to quantify and understand the role of this burnt carbon, which is not emitted to the atmosphere, as a sink enriched in carbon.

  4. Total Land Water Storage Change over 2003 - 2013 Estimated from a Global Mass Budget Approach

    NASA Technical Reports Server (NTRS)

    Dieng, H. B.; Champollion, N.; Cazenave, A.; Wada, Y.; Schrama, E.; Meyssignac, B.

    2015-01-01

    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 +/- 0.18 mm/yr in sea level equivalent. This corresponds to a net decrease of -108 +/- 64 cu km/yr in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

  5. Total land water storage change over 2003-2013 estimated from a global mass budget approach

    NASA Astrophysics Data System (ADS)

    Dieng, H. B.; Champollion, N.; Cazenave, A.; Wada, Y.; Schrama, E.; Meyssignac, B.

    2015-12-01

    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 ± 0.18 mm yr-1 in sea level equivalent. This corresponds to a net decrease of -108 ± 64 km3 yr-1 in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

  6. Total land water storage change over 2003-2013 estimated from a global mass budget approach

    NASA Astrophysics Data System (ADS)

    Dieng, Habib B.; Champollion, Nicolas; Cazenave, Anny; Wada, Yoshihide; Schrama, Ernst; Meyssignac, Benoit

    2016-04-01

    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS(the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to+0.30 ± 0.18mmyr‑1 in sea level equivalent. This corresponds to a net decrease of ‑108 ± 64 km3 yr‑1 in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

  7. Incorrect interpretation of carbon mass balance biases global vegetation fire emission estimates

    PubMed Central

    Surawski, N. C.; Sullivan, A. L.; Roxburgh, S. H.; Meyer, C.P. Mick; Polglase, P. J.

    2016-01-01

    Vegetation fires are a complex phenomenon in the Earth system with many global impacts, including influences on global climate. Estimating carbon emissions from vegetation fires relies on a carbon mass balance technique that has evolved with two different interpretations. Databases of global vegetation fire emissions use an approach based on ‘consumed biomass', which is an approximation to the biogeochemically correct ‘burnt carbon' approach. Here we show that applying the ‘consumed biomass' approach to global emissions from vegetation fires leads to annual overestimates of carbon emitted to the atmosphere by 4.0% or 100 Tg compared with the ‘burnt carbon' approach. The required correction is significant and represents ∼9% of the net global forest carbon sink estimated annually. Vegetation fire emission studies should use the ‘burnt carbon' approach to quantify and understand the role of this burnt carbon, which is not emitted to the atmosphere, as a sink enriched in carbon. PMID:27146785

  8. Global Mass Flux Solutions from GRACE: A Comparison of Parameter Estimation Strategies - Mass Concentrations Versus Stokes Coefficients

    NASA Technical Reports Server (NTRS)

    Rowlands, D. D.; Luthcke, S. B.; McCarthy J. J.; Klosko, S. M.; Chinn, D. S.; Lemoine, F. G.; Boy, J.-P.; Sabaka, T. J.

    2010-01-01

    The differences between mass concentration (mas con) parameters and standard Stokes coefficient parameters in the recovery of gravity infonnation from gravity recovery and climate experiment (GRACE) intersatellite K-band range rate data are investigated. First, mascons are decomposed into their Stokes coefficient representations to gauge the range of solutions available using each of the two types of parameters. Next, a direct comparison is made between two time series of unconstrained gravity solutions, one based on a set of global equal area mascon parameters (equivalent to 4deg x 4deg at the equator), and the other based on standard Stokes coefficients with each time series using the same fundamental processing of the GRACE tracking data. It is shown that in unconstrained solutions, the type of gravity parameter being estimated does not qualitatively affect the estimated gravity field. It is also shown that many of the differences in mass flux derivations from GRACE gravity solutions arise from the type of smoothing being used and that the type of smoothing that can be embedded in mas con solutions has distinct advantages over postsolution smoothing. Finally, a 1 year time series based on global 2deg equal area mascons estimated every 10 days is presented.

  9. Satellite-based global-ocean mass balance estimates of interannual variability and emerging trends in continental freshwater discharge

    PubMed Central

    Syed, Tajdarul H.; Famiglietti, James S.; Chambers, Don P.; Willis, Josh K.; Hilburn, Kyle

    2010-01-01

    Freshwater discharge from the continents is a key component of Earth’s water cycle that sustains human life and ecosystem health. Surprisingly, owing to a number of socioeconomic and political obstacles, a comprehensive global river discharge observing system does not yet exist. Here we use 13 years (1994–2006) of satellite precipitation, evaporation, and sea level data in an ocean mass balance to estimate freshwater discharge into the global ocean. Results indicate that global freshwater discharge averaged 36,055 km3/y for the study period while exhibiting significant interannual variability driven primarily by El Niño Southern Oscillation cycles. The method described here can ultimately be used to estimate long-term global discharge trends as the records of sea level rise and ocean temperature lengthen. For the relatively short 13-year period studied here, global discharge increased by 540 km3/y2, which was largely attributed to an increase of global-ocean evaporation (768 km3/y2). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle. PMID:20921364

  10. Satellite-based global-ocean mass balance estimates of interannual variability and emerging trends in continental freshwater discharge.

    PubMed

    Syed, Tajdarul H; Famiglietti, James S; Chambers, Don P; Willis, Josh K; Hilburn, Kyle

    2010-10-19

    Freshwater discharge from the continents is a key component of Earth's water cycle that sustains human life and ecosystem health. Surprisingly, owing to a number of socioeconomic and political obstacles, a comprehensive global river discharge observing system does not yet exist. Here we use 13 years (1994-2006) of satellite precipitation, evaporation, and sea level data in an ocean mass balance to estimate freshwater discharge into the global ocean. Results indicate that global freshwater discharge averaged 36,055 km(3)/y for the study period while exhibiting significant interannual variability driven primarily by El Niño Southern Oscillation cycles. The method described here can ultimately be used to estimate long-term global discharge trends as the records of sea level rise and ocean temperature lengthen. For the relatively short 13-year period studied here, global discharge increased by 540 km(3)/y(2), which was largely attributed to an increase of global-ocean evaporation (768 km(3)/y(2)). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle. PMID:20921364

  11. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    NASA Astrophysics Data System (ADS)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-10-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil-fuel and biomass-burning BC. In addition we develop a global simulation of brown carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of 2. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in absorption aerosol optical depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with the largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 Wm-2 (0.08 Wm-2 from anthropogenic sources and 0.05 Wm-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 Wm-2, with an additional +0.11 Wm-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80%/+140%. Our estimates are at the lower end of the 0.2-1.0 Wm-2 range from previous studies, and substantially less than the +0.6 Wm-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime (including the

  12. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    NASA Astrophysics Data System (ADS)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-06-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil fuel and biomass burning BC. In addition we develop a global simulation of Brown Carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of two. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in Absorption Aerosol Optical Depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 W m-2 (0.08 W m-2 from anthropogenic sources and 0.05 W m-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 W m-2, with an additional +0.11 W m-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80% / +140%. Our estimates are at the lower end of the 0.2-1.0 W m-2 range from previous studies, and substantially less than the +0.6 W m-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime and the

  13. Global Warming Estimation from MSU

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, Robert, Jr.

    1999-01-01

    In this study, we have developed time series of global temperature from 1980-97 based on the Microwave Sounding Unit (MSU) Ch 2 (53.74 GHz) observations taken from polar-orbiting NOAA operational satellites. In order to create these time series, systematic errors (approx. 0.1 K) in the Ch 2 data arising from inter-satellite differences are removed objectively. On the other hand, smaller systematic errors (approx. 0.03 K) in the data due to orbital drift of each satellite cannot be removed objectively. Such errors are expected to remain in the time series and leave an uncertainty in the inferred global temperature trend. With the help of a statistical method, the error in the MSU inferred global temperature trend resulting from orbital drifts and residual inter-satellite differences of all satellites is estimated to be 0.06 K decade. Incorporating this error, our analysis shows that the global temperature increased at a rate of 0.13 +/- 0.06 K decade during 1980-97.

  14. Spacecraft telecommunications system mass estimates

    NASA Technical Reports Server (NTRS)

    Yuen, J. H.; Sakamoto, L. L.

    1988-01-01

    Mass is the most important limiting parameter for present-day planetary spacecraft design, In fact, the entire design can be characterized by mass. The more efficient the design of the spacecraft, the less mass will be required. The communications system is an essential and integral part of planetary spacecraft. A study is presented of the mass attributable to the communications system for spacecraft designs used in recent missions in an attempt to help guide future design considerations and research and development efforts. The basic approach is to examine the spacecraft by subsystem and allocate a portion of each subsystem to telecommunications. Conceptually, this is to divide the spacecraft into two parts, telecommunications and nontelecommunications. In this way, it is clear what the mass attributable to the communications system is. The percentage of mass is calculated using the actual masses of the spacecraft parts, except in the case of CRAF. In that case, estimated masses are used since the spacecraft was not yet built. The results show that the portion of the spacecraft attributable to telecommunications is substantial. The mass fraction for Voyager, Galileo, and CRAF (Mariner Mark 2) is 34, 19, and 18 percent, respectively. The large reduction of telecommunications mass from Voyager to Galileo is mainly due to the use of a deployable antenna instead of the solid antenna on Voyager.

  15. Global Acceleration of Coronal Mass Ejections

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Nat; Lara, Alejandro; Lepping, Ronald; Kaiser, Michael; Berdichevsky, Daniel; St. Cyr, O. Chris; Lazarus, Al

    1999-01-01

    Using the observed relation between speeds of coronal mass ejections (CMEs) near the Sun and in the solar wind, we estimate a global acceleration acting on the CMEs. Our study quantifies the qualitative results of Gosling [1997] and numerical simulations that CMEs at 1 AU with speeds closer to the solar wind. We found a linear relation between the global acceleration and the initial speed of the CMEs and the absolute value of the acceleration is similar to the slow solar wind acceleration. Our study naturally divides CMEs into fast and slow ones, the dividing line being the solar wind speed. Our results have important implications to space weather prediction models which need to incorporate this effect in estimating the CME arrival time at 1 AU. We show that the arrival times of CMEs at 1 AU are drastically different from the zero acceleration case.

  16. APPROACH FOR ESTIMATING GLOBAL LANDFILL METHANE EMISSIONS

    EPA Science Inventory

    The report is an overview of available country-specific data and modeling approaches for estimating global landfill methane. Current estimates of global landfill methane indicate that landfills account for between 4 and 15% of the global methane budget. The report describes an ap...

  17. Global Warming Estimation from MSU

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, Robert; Yoo, Jung-Moon

    1998-01-01

    Microwave Sounding Unit (MSU) radiometer observations in Ch 2 (53.74 GHz) from sequential, sun-synchronous, polar-orbiting NOAA satellites contain small systematic errors. Some of these errors are time-dependent and some are time-independent. Small errors in Ch 2 data of successive satellites arise from calibration differences. Also, successive NOAA satellites tend to have different Local Equatorial Crossing Times (LECT), which introduce differences in Ch 2 data due to the diurnal cycle. These two sources of systematic error are largely time independent. However, because of atmospheric drag, there can be a drift in the LECT of a given satellite, which introduces time-dependent systematic errors. One of these errors is due to the progressive chance in the diurnal cycle and the other is due to associated chances in instrument heating by the sun. In order to infer global temperature trend from the these MSU data, we have eliminated explicitly the time-independent systematic errors. Both of the time-dependent errors cannot be assessed from each satellite. For this reason, their cumulative effect on the global temperature trend is evaluated implicitly. Christy et al. (1998) (CSL). based on their method of analysis of the MSU Ch 2 data, infer a global temperature cooling trend (-0.046 K per decade) from 1979 to 1997, although their near nadir measurements yield near zero trend (0.003 K/decade). Utilising an independent method of analysis, we infer global temperature warmed by 0.12 +/- 0.06 C per decade from the observations of the MSU Ch 2 during the period 1980 to 1997.

  18. Surface term effects on mass estimators

    NASA Astrophysics Data System (ADS)

    Membrado, M.; Pacheco, A. F.

    2016-05-01

    Context. We propose a way of estimating the mass contained in the volume occupied by a sample of galaxies in a virialized system. Aims: We analyze the influence of surface effects and the contribution of the cosmological constant terms on our mass estimations of galaxy systems. Methods: We propose two equations that contain surface terms to estimate galaxy sample masses. When the surface terms are neglected, these equations provide the so-called virial and projected masses. Both equations lead to a single equation that allows sample masses to be estimated without the need for calculating surface terms. Sample masses for some nearest galaxy groups are estimated and compared with virialized masses determined from turn-around radii and results of a spherical infall model. Results: Surface effects have a considerable effect on the mass estimations of the studied galaxy groups. According to our results, they lead sample masses of some groups to being less than half the virial mass estimations and even less than 10% of projected mass estimations. However, the contributions of cosmological constant terms to mass estimations are smaller than 2% for the majority of the virialized groups studied. Our estimations are in agreement with virialized masses calculated from turn-around radii. Virialized masses for complexes were found to be: (8.9 ± 2.8) × 1011 M⊙ for the Milky Way - M 31; (12.5 ± 2.5) × 1011 M⊙ for M 81 - NGC 2403; (21.5 ± 7.7) × 1011 M⊙. for Cantaurs A - M 83; and (7.9 ± 2.6) × 1011 M⊙. for IC 324 - Maffei. Conclusions: The nearest galaxy groups located inside a sphere of 5 Mpc have been addressed to explore the performance of our mass estimator. We have seen that surface effects make mass estimations of galaxy groups rather smaller than both virial and projected masses. In mass calculations, cosmological constant terms can be neglected; nevertheless, the collapse of cold dark matter leading to virialized structures is strongly affected by the

  19. Mass Transport in Global Geophysical Fluids

    NASA Technical Reports Server (NTRS)

    Chao, B. F.

    1999-01-01

    Mass transports occurring in the atmosphere-hydrosphere-solid Earth-core system (the "global geophysical fluids") are important geophysical phenomena. They occur on all temporal and spatial scales. Examples include air mass and ocean circulations, tides, hydrological water redistribution, mantle processes such as post-glacial rebound, earthquakes and tectonic motions, and core geodynamo activities. With only a few exceptions on the Earth surface, the temporal history and spatial pattern of such mass transport are often not amenable to direct observations. Space geodesy techniques, however, have the capability of monitoring certain direct consequences of the mass transport, including Earth's rotation variations, gravitational field variations, and the geocenter motion. These techniques include the very-long-baseline interferometry, satellite laser ranging and Doppler tracking, and the Global Positioning System, all entail global observational networks. While considerable advances have been made in observing and understanding of the dynamics of Earth's rotation, only the lowest-degree gravitational variations have been observed and limited knowledge of geocenter motion obtained. New space missions, projects and initiatives promise to further improve the measurements and hence our knowledge about the global mass transports. The latter contributes to our understanding and modeling capability of the geophysical processes that produce and regulate the mass transports, as well as the solid Earth's response to such changes in constraining the modeling of Earth's mechanical properties.

  20. Global Response to Local Ionospheric Mass Ejection

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Fok, M.-C.; Delcourt, D. C.; Slinker, S. P.; Fedder, J. A.

    2010-01-01

    We revisit a reported "Ionospheric Mass Ejection" using prior event observations to guide a global simulation of local ionospheric outflows, global magnetospheric circulation, and plasma sheet pressurization, and comparing our results with the observed global response. Our simulation framework is based on test particle motions in the Lyon-Fedder-Mobarry (LFM) global circulation model electromagnetic fields. The inner magnetosphere is simulated with the Comprehensive Ring Current Model (CRCM) of Fok and Wolf, driven by the transpolar potential developed by the LFM magnetosphere, and includes an embedded plasmaspheric simulation. Global circulation is stimulated using the observed solar wind conditions for the period 24-25 Sept 1998. This period begins with the arrival of a Coronal Mass Ejection, initially with northward, but later with southward interplanetary magnetic field. Test particles are launched from the ionosphere with fluxes specified by local empirical relationships of outflow to electrodynamic and particle precipitation imposed by the MIlD simulation. Particles are tracked until they are lost from the system downstream or into the atmosphere, using the full equations of motion. Results are compared with the observed ring current and a simulation of polar and auroral wind outflows driven globally by solar wind dynamic pressure. We find good quantitative agreement with the observed ring current, and reasonable qualitative agreement with earlier simulation results, suggesting that the solar wind driven global simulation generates realistic energy dissipation in the ionosphere and that the Strangeway relations provide a realistic local outflow description.

  1. Estimating Global Precipitation for Science and Application

    NASA Technical Reports Server (NTRS)

    Huffman, George J.

    2013-01-01

    Over the past two decades there has been vigorous development in the satellite assets and the algorithms necessary to estimate precipitation around the globe. In particular the highly successful joint NASAJAXA Tropical Rainfall Measuring Mission (TRMM) and the upcoming Global Precipitation Measurement (GPM) mission, also joint between NASA and JAXA, have driven these issues. At the same time, the long-running Global Precipitation Climatology Project (GPCP) continues to extend a stable, climate-oriented view of global precipitation. This talk will provide an overview of these projects and the wider international community of precipitation datasets, sketch plans for next-generation products, and provide some examples of the best use for the different products. One key lesson learned is that different data sets are needed to address the variety of issues that need precipitation data, including detailed 3-D views of hurricanes, flash flood forecasting, drought analysis, and global change.

  2. Volcanism, global catastrophe and mass mortality

    NASA Technical Reports Server (NTRS)

    Francis, P. W.; Burke, K.

    1988-01-01

    The effects of very large volcanic eruptions are well documented in many studies, mostly based on observations made on three historic eruptions, Laki 1783; Tambora 1815 and Krakatau 1883. Such eruptions have effects that are catastrophic locally and measurable globally, but it is not clear that even the largest volcanic eruptions have had global catastrophic effects, nor caused mass extinctions. Two different types of volcanic eruption were considered as likely to have the most serious widespread effects: large silicic explosive eruptions producing hundreds or thousands of cubic kilometers of pyroclastic materials, and effusive basaltic eruptions producing of approximately 100 cubic kilometers of lava. In both cases, the global effects are climatic, and attributable to production of stratospheric aerosols. Other possibilities need to be explored. Recent research on global change has emphasized the extreme sensitivity of the links between oceanic circulation, atmospheric circulation and climate. In particular, it was argued that the pattern of ocean current circulation (which strongly influences climate) is unstable; it may rapidly flip from one pattern to a different one, with global climatic consequences. If volcanism has been a factor in global environmental change and a cause of mass extinctions, it seems most likely that it has done so by providing a trigger to other processes, for example by driving oceanic circulation from one mode to another.

  3. Black Hole Mass Estimation: How Good is the Virial Estimate?

    NASA Astrophysics Data System (ADS)

    Yong, Suk Yee; Webster, Rachel L.; King, Anthea L.

    2016-03-01

    Black hole mass is a key factor in determining how a black hole interacts with its environment. However, the determination of black hole masses at high redshifts depends on secondary mass estimators, which are based on empirical relationships and broad approximations. A dynamical disk wind broad line region model (BLR) of active galactic nuclei is built in order to test the impact of different BLR geometries and inclination angles on the black hole mass estimation. Monte Carlo simulations of two disk wind models are constructed to recover the virial scale factor, f, at various inclination angles. The resulting f values strongly correlate with inclination angle, with large f values associated with small inclination angles (close to face-on) and small f values with large inclination angles (close to edge-on). The recovered f factors are consistent with previously determined f values, found from empirical relationships. Setting f as a constant may introduce a bias into virial black hole mass estimates for a large sample of active galactic nuclei. However, the extent of the bias depends on the line width characterisation (e.g. full width at half maximum or line dispersion). Masses estimated using f_{FWHM} tend to be biased towards larger masses, but this can generally be corrected by calibrating for the width or shape of the emission line.

  4. Orientation and quasar black hole mass estimation

    NASA Astrophysics Data System (ADS)

    Brotherton, Michael S.; Singh, Vikram; Runnoe, Jessie

    2015-12-01

    We have constructed a sample of 386 radio-loud quasars with z < 0.75 from the Sloan Digital Sky Survey in order to investigate orientation effects on black hole mass estimates. Orientation is estimated using radio core dominance measurements based on FIRST survey maps. Black hole masses are estimated from virial-based scaling relationships using Hβ, and compared to the stellar velocity dispersion (σ*), predicted using the full width at half maximum (FWHM) of [O III] λ5007, which tracks mass via the M-σ* relation. We find that the FWHM of Hβ correlates significantly with radio core dominance and biases black hole mass determinations that use it, but that this is not the case for σ* based on [O III] λ5007. The ratio of black hole masses predicted using orientation-biased and unbiased estimates, which can be determined for radio-quiet as well as radio-loud quasars, is significantly correlated with radio core dominance. Although there is significant scatter, this mass ratio calculated in this way may in fact serve as an orientation estimator. We additionally note the existence of a small population of radio core-dominated quasars with extremely broad Hβ emission lines that we hypothesize may represent recent black hole mergers.

  5. Estimating pre-industrial global temperature

    NASA Astrophysics Data System (ADS)

    Hawkins, Ed; Ortega, Pablo; Suckling, Emma; Schurer, Andrew; Hegerl, Gabi; Jones, Phil; Joshi, Manoj; Osborn, Tim; Mignot, Juliette; Thorne, Peter; van Oldenborgh, Geert Jan

    2016-04-01

    The United Nations Framework Convention on Climate Change (UNFCCC) process has recently agreed to try and limit global temperature rise to `well below 2°C above pre-industrial levels'. But what period is `pre-industrial'? Remarkably, perhaps, this is not defined within the UNFCCC or its many agreements and protocols. Neither was the term used in the IPCC's fifth assessment report (AR5) when discussing when particular temperature levels might be reached, due to the lack of a robust definition. Here, we discuss the important factors to consider when defining a period to call pre-industrial, based on estimates of historical radiative forcings and the availability of climate observations. There is no perfect period to choose, but we suggest that 1720-1800 is the optimal choice. We also attempt to estimate the change in global temperatures since this pre-industrial period using a range of approaches based on observations, radiative forcings, global climate model simulations and proxy evidence. We discuss how such an assessment might be improved in future and conclude that 2015 was likely the first year in which global temperatures were more than 1°C above pre-industrial levels.

  6. Global estimates of fresh submarine groundwater discharge

    NASA Astrophysics Data System (ADS)

    Luijendijk, Elco; Gleeson, Tom; Moosdorf, Nils

    2016-04-01

    Fresh submarine groundwater discharge, the flow of fresh groundwater to oceans, may be a significant contributor to the water and chemical budgets of the world's oceans. We present new estimates of the flux of fresh groundwater to the world's oceans. We couple density-dependent numerical simulations of generic models of coastal basins with geospatial databases of hydrogeological parameters and topography to resolve the rate of terrestrially-derived submarine groundwater discharge globally. We compare the model results to a new global compilation of submarine groundwater discharge observations. The results show that terrestrially-derived SGD is highly sensitive to permeability. In most watersheds only a small fraction of groundwater recharge contributes to submarine groundwater discharge, with most recharge instead contributing to terrestrial discharge in the form of baseflow or evapotranspiration. Fresh submarine groundwater discharge is only significant in watersheds that contain highly permeable sediments, such as coarse-grained siliciclastic sediments, karstic carbonates or volcanic deposits. Our estimates of global submarine groundwater discharge are much lower than most previous estimates. However, many tropical and volcanic islands are hotspots of submarine groundwater discharge and solute fluxes towards the oceans. The comparison of model results and data highlights the spatial variability of SGD and the difficulty of scaling up observations.

  7. Estimates of doses from global fallout.

    PubMed

    Bouville, André; Simon, Steven L; Miller, Charles W; Beck, Harold L; Anspaugh, Lynn R; Bennett, Burton G

    2002-05-01

    This paper summarizes information about external and internal doses resulting from global fallout and presents preliminary estimates of doses resulting from intermediate fallout in the contiguous United States. Most of the data on global fallout were extracted from the reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, in which the radiation exposures from fallout have been extensively reviewed at regular intervals. United Nations Scientific Committee on the Effects of Atomic Radiation estimated the average effective doses received by the world's population before 2000 to be about 0.4 mSv from external irradiation and 0.6 mSv from internal irradiation, the main radionuclide contributing to the effective dose being 137Cs. Effective doses received beyond 2000 result mainly from the environmentally mobile, long-lived 14C and amount to about 2.5 mSv summed over present and future generations. Specific information about the doses from fallout received by the United States population is based on the preliminary results of a study requested by the U.S. Congress and conducted jointly by the Centers for Disease Control and Prevention and the National Cancer Institute. Separate calculations were made for the tests conducted at the Nevada Test Site and for the high-yield tests conducted mainly by the United States and the former Soviet Union at sites far away from the contiguous United States (global tests). The estimated average doses from external irradiation received by the United States population were about 0.5 mGy for Nevada Test Site fallout and about 0.7 mGy for global fallout. These values vary little from one organ or tissue of the body to another. In contrast, the average doses from internal irradiation vary markedly from one organ or tissue to another; estimated average thyroid doses to children born in 1951 were about 30 mGy from Nevada Test Site fallout and about 2 mGy from global fallout. PMID:12003019

  8. Global Civil Aviation Black Carbon Particle Mass and Number Emissions

    NASA Astrophysics Data System (ADS)

    Stettler, M. E. J.

    2015-12-01

    Black carbon (BC) is a product of incomplete combustion emitted by aircraft engines. In the atmosphere, BC particles strongly absorb incoming solar radiation and influence cloud formation processes leading to highly uncertain, but likely net positive warming of the earth's atmosphere. At cruise altitude, BC particle number emissions can influence the concentration of ice nuclei that can lead to contrail formation, with significant and highly uncertainty climate impacts. BC particles emitted by aircraft engines also degrade air quality in the vicinity of airports and globally. A significant contribution to the uncertainty in environmental impacts of aviation BC emissions is the uncertainty in emissions inventories. Previous work has shown that global aviation BC mass emissions are likely to have been underestimated by a factor of three. In this study, we present an updated global BC particle number inventory and evaluate parameters that contribute to uncertainty using global sensitivity analysis techniques. The method of calculating particle number from mass utilises a description of the mobility of fractal aggregates and uses the geometric mean diameter, geometric standard deviation, mass-mobility exponent, primary particle diameter and material density to relate the particle number concentration to the total mass concentration. Model results show good agreement with existing measurements of aircraft BC emissions at ground level and at cruise altitude. It is hoped that the results of this study can be applied to estimate direct and indirect climate impacts of aviation BC emissions in future studies.

  9. Modern Estimates of Global Water Cycle Fluxes

    NASA Astrophysics Data System (ADS)

    Rodell, M.; Beaudoing, H. K.; L'Ecuyer, T. S.; Olson, W. S.

    2014-12-01

    The goal of the first phase of the NASA Energy and Water Cycle Study (NEWS) Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. Here we describe results of the water cycle assessment, including mean annual and monthly fluxes over continents and ocean basins during the first decade of the millennium. To the extent possible, the water flux estimates are based on (1) satellite measurements and (2) data-integrating models. A careful accounting of uncertainty in each flux was applied within a routine that enforced multiple water and energy budget constraints simultaneously in a variational framework, in order to produce objectively-determined, optimized estimates. Simultaneous closure of the water and energy budgets caused the ocean evaporation and precipitation terms to increase by about 10% and 5% relative to the original estimates, mainly because the energy budget required turbulent heat fluxes to be substantially larger in order to balance net radiation. In the majority of cases, the observed annual, surface and atmospheric water budgets over the continents and oceans close with much less than 10% residual. Observed residuals and optimized uncertainty estimates are considerably larger for monthly surface and atmospheric water budget closure, often nearing or exceeding 20% in North America, Eurasia, Australia and neighboring islands, and the Arctic and South Atlantic Oceans. The residuals in South America and Africa tend to be smaller, possibly because cold land processes are a non-issue. Fluxes are poorly observed over the Arctic Ocean, certain seas, Antarctica, and the Australasian and Indonesian Islands, leading to reliance on atmospheric analysis estimates. Other details of the study and future directions will be discussed.

  10. CORONAL MASS EJECTION MASS, ENERGY, AND FORCE ESTIMATES USING STEREO

    SciTech Connect

    Carley, Eoin P.; Gallagher, Peter T.; McAteer, R. T. James

    2012-06-10

    Understanding coronal mass ejection (CME) energetics and dynamics has been a long-standing problem, and although previous observational estimates have been made, such studies have been hindered by large uncertainties in CME mass. Here, the two vantage points of the Solar Terrestrial Relations Observatory (STEREO) COR1 and COR2 coronagraphs were used to accurately estimate the mass of the 2008 December 12 CME. Acceleration estimates derived from the position of the CME front in three dimensions were combined with the mass estimates to calculate the magnitude of the kinetic energy and driving force at different stages of the CME evolution. The CME asymptotically approaches a mass of 3.4 {+-} 1.0 Multiplication-Sign 10{sup 15} g beyond {approx}10 R{sub Sun }. The kinetic energy shows an initial rise toward 6.3 {+-} 3.7 Multiplication-Sign 10{sup 29} erg at {approx}3 R{sub Sun }, beyond which it rises steadily to 4.2 {+-} 2.5 Multiplication-Sign 10{sup 30} erg at {approx}18 R{sub Sun }. The dynamics are described by an early phase of strong acceleration, dominated by a force of peak magnitude of 3.4 {+-} 2.2 Multiplication-Sign 10{sup 14} N at {approx}3 R{sub Sun }, after which a force of 3.8 {+-} 5.4 Multiplication-Sign 10{sup 13} N takes effect between {approx}7 and 18 R{sub Sun }. These results are consistent with magnetic (Lorentz) forces acting at heliocentric distances of {approx}<7 R{sub Sun }, while solar wind drag forces dominate at larger distances ({approx}>7 R{sub Sun }).

  11. Atmospheric methyl bromide: Trends and global mass balance

    SciTech Connect

    Khalil, M.A.K.; Rasmussen, R.A.; Gunawardena, R. )

    1993-02-20

    Atmospheric methyl bromide is of considerable environmental importance as the largest reservoir of gaseous bromine in the atmosphere. Bromine gases can catalytically destroy stratospheric ozone. Since agricultural activities, automobiles, biomass burning, and other human activities produce CH[sub 3]Br, it is of interest to know its global mass balance and particularly the specific sources and sinks. In this paper the authors provide a decadal time series of global CH[sub 3]Br concentrations in the Earth's atmosphere. The data show that average concentrations are about 10 pptv and during the last 4 years may be increasing at 0.3 [plus minus] 0.1 pptv/yr (3%/yr [plus minus] 1%/yr). They estimate that the atmospheric lifetime of CH[sub 3]Br that is due to reaction with OH, is about 2 years, resulting in a calculated global emission rate of about 100 Gy/yr. Ocean supersaturations of 140-180% are observed, and atmospheric concentrations over the open oceans are higher than at comparably located coastal sites. The ocean source is estimated to be about 35 Gg/yr. The remaining emissions must come from other natural sources and anthropogenic activities. The results are based on some 2,200 samples obtained over more than a decade. Mass balance calculations explain most aspects of the present data but other implications are not easily reconciled, leaving open the possibility of undiscovered sources and sinks. 20 refs., 5 figs., 4 tabs.

  12. Climatology of globally averaged thermospheric mass density

    NASA Astrophysics Data System (ADS)

    Emmert, J. T.; Picone, J. M.

    2010-09-01

    We present a climatological analysis of daily globally averaged density data, derived from orbit data and covering the years 1967-2007, along with an empirical Global Average Mass Density Model (GAMDM) that encapsulates the 1986-2007 data. The model represents density as a function of the F10.7 solar radio flux index, the day of year, and the Kp geomagnetic activity index. We discuss in detail the dependence of the data on each of the input variables, and demonstrate that all of the terms in the model represent consistent variations in both the 1986-2007 data (on which the model is based) and the independent 1967-1985 data. We also analyze the uncertainty in the results, and quantify how the variance in the data is apportioned among the model terms. We investigate the annual and semiannual variations of the data and quantify the amplitude, height dependence, solar cycle dependence, and interannual variability of these oscillatory modes. The auxiliary material includes Fortran 90 code for evaluating GAMDM.

  13. A Reconciled Estimate of Ice-Sheet Mass Balance

    NASA Technical Reports Server (NTRS)

    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.

  14. A reconciled estimate of ice-sheet mass balance.

    PubMed

    Shepherd, Andrew; Ivins, Erik R; A, Geruo; Barletta, Valentina R; Bentley, Mike J; Bettadpur, Srinivas; Briggs, Kate H; Bromwich, David H; Forsberg, René; 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; Sørensen, Louise Sandberg; Scambos, Ted A; Scheuchl, Bernd; Schrama, Ernst J O; Smith, Ben; Sundal, Aud V; van Angelen, Jan H; van de Berg, Willem J; van den Broeke, Michiel R; Vaughan, David G; Velicogna, Isabella; Wahr, John; Whitehouse, Pippa L; Wingham, Duncan J; Yi, Donghui; Young, Duncan; Zwally, H Jay

    2012-11-30

    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. PMID:23197528

  15. Lean body mass estimation by creatinine kinetics.

    PubMed

    Keshaviah, P R; Nolph, K D; Moore, H L; Prowant, B; Emerson, P F; Meyer, M; Twardowski, Z J; Khanna, R; Ponferrada, L; Collins, A

    1994-01-01

    A new technique for estimating lean body mass (LBM) from creatinine kinetics has been developed. It is based on the principle that creatinine production is proportional to LBM and that, in the steady state, creatinine production is equal to the sum of creatinine excretion (urinary and dialytic) and metabolic degradation. This technique was applied to 17 normal subjects, 26 stable, chronic hemodialysis (HD) patients, and 71 stable, chronic peritoneal dialysis (PD) patients. In the HD group, LBM was also determined by bioimpedance in 11 patients and calculated from total body water, measured as the volume of urea distribution of a sterile urea infusion, in 15 patients. In normal subjects and in the PD group, LBM was assessed by creatinine kinetics as well as by bioimpedance, near infrared, and anthropometric techniques. In the HD patients, LBM by creatinine kinetics correlated significantly with LBM from total body water and the bioimpedance technique. There was no statistical difference between the total body water and creatinine kinetics techniques, but the bioimpedance values were systematically higher than those obtained by the kinetic technique. In the PD group and in normal volunteers, LBM values by creatinine kinetics correlated significantly with the other methods but were lower. Forty-seven percent of the HD patients and 66% of the PD patients had significantly lower LBM by creatinine kinetics than expected for their sex and age. Estimation of LBM by creatinine kinetics is proposed as a simple and convenient technique for the routine nutritional assessment of dialysis patients. PMID:8161729

  16. Global Warming Estimation From Microwave Sounding Unit

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Dalu, G.

    1998-01-01

    Microwave Sounding Unit (MSU) Ch 2 data sets, collected from sequential, polar-orbiting, Sun-synchronous National Oceanic and Atmospheric Administration operational satellites, contain systematic calibration errors that are coupled to the diurnal temperature cycle over the globe. Since these coupled errors in MSU data differ between successive satellites, it is necessary to make compensatory adjustments to these multisatellite data sets in order to determine long-term global temperature change. With the aid of the observations during overlapping periods of successive satellites, we can determine such adjustments and use them to account for the coupled errors in the long-term time series of MSU Ch 2 global temperature. In turn, these adjusted MSU Ch 2 data sets can be used to yield global temperature trend. In a pioneering study, Spencer and Christy (SC) (1990) developed a procedure to derive the global temperature trend from MSU Ch 2 data. Such a procedure can leave unaccounted residual errors in the time series of the temperature anomalies deduced by SC, which could lead to a spurious long-term temperature trend derived from their analysis. In the present study, we have developed a method that avoids the shortcomings of the SC procedure, the magnitude of the coupled errors is not determined explicitly. Furthermore, based on some assumptions, these coupled errors are eliminated in three separate steps. Such a procedure can leave unaccounted residual errors in the time series of the temperature anomalies deduced by SC, which could lead to a spurious long-term temperature trend derived from their analysis. In the present study, we have developed a method that avoids the shortcomings of the SC procedures. Based on our analysis, we find there is a global warming of 0.23+/-0.12 K between 1980 and 1991. Also, in this study, the time series of global temperature anomalies constructed by removing the global mean annual temperature cycle compares favorably with a similar

  17. A Global Assessment of Accelerations in Mass Transport of Surface Geophysical Fluid

    NASA Astrophysics Data System (ADS)

    Wu, X.; Heflin, M. B.

    2015-12-01

    Mass transport in the Earth's surface geophysical fluid layer has complex spatiotemporal patterns. The GRACE gravity mission provides an unprecedented global capability to monitor this important process with high accuracy and resolution. Accurate assessments of global mass transport patterns and budget also depend critically on changes in degree-1 coefficients (geocenter motion) and in Earth's dynamic oblateness coefficient J2. We combine GRACE measurements, time series of GNSS data, JPL's ECCO ocean bottom pressure model, and high-resolution loose a priori models of mass variation regimes to derive complete spherical harmonic spectra of detrended mass variations up to degree and order 180. Mass accelerations are estimated along with linear, annual, semiannual, and the 161-day tidal aliasing components from coefficient time series. The appropriateness of a priori information and estimate uncertainties are further evaluated by variance component estimation and residual statistics of fitting the time series. During the GRACE data period of 2002.2-2015.0, accelerations in mass transport are geographically uneven with significant positive or negative accelerations in various parts of the world. While Greenland and West Antarctica show strong accelerated mass losses, Alaska and the Arctic Ocean have significant positive accelerations with reversals of earlier mass loss trends. No evidence of non-Arctic global mean sea level acceleration due to mass has been found. Depending on region, some estimated accelerations are also not steady over time due to large irregular and interannual variations.

  18. RSMASS: A simple model for estimating reactor/shield masses

    NASA Technical Reports Server (NTRS)

    Marshall, Albert C.

    1987-01-01

    A comparison was completed of the reactor/shield masses obtained from detailed calculations by the proposers of space power reactors. This comparison included a variety of liquid metal cooled, gas cooled and thermionic reactors. An initial goal for agreement between RSMASS (reactor/shield mass model) calculated masses and the masses obtained from detailed calculations was chosen to be a factor of 2. The preliminary comparison demonstrated that the reactor/shield masses estimated by RSMASS agree with the masses obtained from detailed calculations within 50 percent. It can be concluded that RSMASS can provide good estimates of reactor/shield masses for a broad variety of reactor concepts proposed for MMW space power applications. RSMASS is being used to compare the masses of various reactor types and is providing some insights into the mass advantages and disadvantages for the various concepts as a function of operating conditions and reactor or shield parameters. Some mass estimates obtained with RSMASS are presented.

  19. The effects of missing data on global ozone estimates

    NASA Technical Reports Server (NTRS)

    Drewry, J. W.; Robbins, J. L.

    1981-01-01

    The effects of missing data and model truncation on estimates of the global mean, zonal distribution, and global distribution of ozone are considered. It is shown that missing data can introduce biased estimates with errors that are not accounted for in the accuracy calculations of empirical modeling techniques. Data-fill techniques are introduced and used for evaluating error bounds and constraining the estimate in areas of sparse and missing data. It is found that the accuracy of the global mean estimate is more dependent on data distribution than model size. Zonal features can be accurately described by 7th order models over regions of adequate data distribution. Data variance accounted for by higher order models appears to represent climatological features of columnar ozone rather than pure error. Data-fill techniques can prevent artificial feature generation in regions of sparse or missing data without degrading high order estimates over dense data regions.

  20. Integrated Estimates of Global Terrestrial Carbon Sequestration

    SciTech Connect

    Thomson, Allison M.; Izaurralde, R Cesar; Smith, Steven J.; Clarke, Leon E.

    2008-02-01

    Assessing the contribution of terrestrial carbon sequestration to international climate change mitigation requires integration across scientific and disciplinary boundaries. As part of a scenario analysis for the US Climate Change Technology Program, measurements and geographic data were used to develop terrestrial carbon sequestration estimates for agricultural soil carbon, reforestation and pasture management. These estimates were then applied in the MiniCAM integrated assessment model to evaluate mitigation strategies within policy and technology scenarios aimed at achieving atmospheric CO2 stabilization by 2100. Adoption of terrestrial sequestration practices is based on competition for land and economic markets for carbon. Terrestrial sequestration reach a peak combined rate of 0.5 to 0.7 Gt carbon yr-1 in mid-century with contributions from agricultural soil (0.21 Gt carbon yr-1), reforestation (0.31 Gt carbon yr-1) and pasture (0.15 Gt carbon yr-1). Sequestration rates vary over time period and with different technology and policy scenarios. The combined contribution of terrestrial sequestration over the next century ranges from 31 to 41 GtC. The contribution of terrestrial sequestration to mitigation is highest early in the century, reaching up to 20% of total carbon mitigation. This analysis provides insight into the behavior of terrestrial carbon mitigation options in the presence and absence of climate change mitigation policies.

  1. Estimation and Validation of Oceanic Mass Circulation from the GRACE Mission

    NASA Technical Reports Server (NTRS)

    Boy, J.-P.; Rowlands, D. D.; Sabaka, T. J.; Luthcke, S. B.; Lemoine, F. G.

    2011-01-01

    Since the launch of the Gravity Recovery And Climate Experiment (GRACE) in March 2002, the Earth's surface mass variations have been monitored with unprecedented accuracy and resolution. Compared to the classical spherical harmonic solutions, global high-resolution mascon solutions allows the retrieval of mass variations with higher spatial and temporal sampling (2 degrees and 10 days). We present here the validation of the GRACE global mascon solutions by comparing mass estimates to a set of about 100 ocean bottom pressure (OSP) records, and show that the forward modelling of continental hydrology prior to the inversion of the K-band range rate data allows better estimates of ocean mass variations. We also validate our GRACE results to OSP variations modelled by different state-of-the-art ocean general circulation models, including ECCO (Estimating the Circulation and Climate of the Ocean) and operational and reanalysis from the MERCATOR project.

  2. ESTIMATE OF GLOBAL METHANE EMISSIONS FROM LANDFILLS AND OPEN DUMPS

    EPA Science Inventory

    The report presents an empirical model to estimate global methane (CH4) emissions from landfills and open dumps based on EPA data from landfill gas (LFG) recovery projects. The EPA CH4 estimates for 1990 range between 19 and 40 teragrams (10 to the 12th power) per year (Tg/yr), w...

  3. Mass and volume contributions to twentieth-century global sea level rise.

    PubMed

    Miller, Laury; Douglas, Bruce C

    2004-03-25

    The rate of twentieth-century global sea level rise and its causes are the subjects of intense controversy. Most direct estimates from tide gauges give 1.5-2.0 mm yr(-1), whereas indirect estimates based on the two processes responsible for global sea level rise, namely mass and volume change, fall far below this range. Estimates of the volume increase due to ocean warming give a rate of about 0.5 mm yr(-1) (ref. 8) and the rate due to mass increase, primarily from the melting of continental ice, is thought to be even smaller. Therefore, either the tide gauge estimates are too high, as has been suggested recently, or one (or both) of the mass and volume estimates is too low. Here we present an analysis of sea level measurements at tide gauges combined with observations of temperature and salinity in the Pacific and Atlantic oceans close to the gauges. We find that gauge-determined rates of sea level rise, which encompass both mass and volume changes, are two to three times higher than the rates due to volume change derived from temperature and salinity data. Our analysis supports earlier studies that put the twentieth-century rate in the 1.5-2.0 mm yr(-1) range, but more importantly it suggests that mass increase plays a larger role than ocean warming in twentieth-century global sea level rise. PMID:15042085

  4. Estimates of global research productivity in virology.

    PubMed

    Falagas, Matthew E; Karavasiou, Antonia I; Bliziotis, Ioannis A

    2005-06-01

    The quantity and quality of published research in the field of Virology by different world regions was estimated in this study. Using the PubMed database, articles from journals included in the "Virology" category of the "Journal Citation Reports" database of the Institute for Scientific Information for the period 1995-2003 were retrieved. The world was divided into nine regions based on geographic, economic, and scientific criteria. Data on the country of origin of the research was available for 33,425 out of 33,712 articles (99.2% of all articles from the included journals). USA exceeds all other world regions in research production for the period studied (42% of total articles), with Western Europe ranking second (35.7%). The mean impact factor in articles published in Virology journals was highest for the USA (4.60), while it was 3.90 for Western Europe and 3.22 for the rest of the world (seven regions combined). USA and Canada ranked first in research productivity when both gross national income per capita (GNIPC) and population were taken into account. The results of this analysis show a distressing fact; the absolute and relative production of research in the field of Virology by the developing regions is very low, although viral diseases cause considerable morbidity and mortality in these areas. It is evident from this study that developing regions need more help from the developed regions to enhance research infrastructure. PMID:15834885

  5. Recursive least square vehicle mass estimation based on acceleration partition

    NASA Astrophysics Data System (ADS)

    Feng, Yuan; Xiong, Lu; Yu, Zhuoping; Qu, Tong

    2014-05-01

    Vehicle mass is an important parameter in vehicle dynamics control systems. Although many algorithms have been developed for the estimation of mass, none of them have yet taken into account the different types of resistance that occur under different conditions. This paper proposes a vehicle mass estimator. The estimator incorporates road gradient information in the longitudinal accelerometer signal, and it removes the road grade from the longitudinal dynamics of the vehicle. Then, two different recursive least square method (RLSM) schemes are proposed to estimate the driving resistance and the mass independently based on the acceleration partition under different conditions. A 6 DOF dynamic model of four In-wheel Motor Vehicle is built to assist in the design of the algorithm and in the setting of the parameters. The acceleration limits are determined to not only reduce the estimated error but also ensure enough data for the resistance estimation and mass estimation in some critical situations. The modification of the algorithm is also discussed to improve the result of the mass estimation. Experiment data on a sphalt road, plastic runway, and gravel road and on sloping roads are used to validate the estimation algorithm. The adaptability of the algorithm is improved by using data collected under several critical operating conditions. The experimental results show the error of the estimation process to be within 2.6%, which indicates that the algorithm can estimate mass with great accuracy regardless of the road surface and gradient changes and that it may be valuable in engineering applications. This paper proposes a recursive least square vehicle mass estimation method based on acceleration partition.

  6. Axion mass estimates from resonant Josephson junctions

    NASA Astrophysics Data System (ADS)

    Beck, Christian

    2015-03-01

    Recently it has been proposed that dark matter axions from the galactic halo can produce a small Shapiro step-like signal in Josephson junctions whose Josephson frequency resonates with the axion mass (Beck, 2013). Here we show that the axion field equations in a voltage-driven Josephson junction environment allow for a nontrivial solution where the axion-induced electrical current manifests itself as an oscillating supercurrent. The linear change of phase associated with this nontrivial solution implies the formal existence of a large magnetic field in a tiny surface area of the weak link region of the junction which makes incoming axions decay into microwave photons. We derive a condition for the design of Josephson junction experiments so that they can act as optimum axion detectors. Four independent recent experiments are discussed in this context. The observed Shapiro step anomalies of all four experiments consistently point towards an axion mass of (110±2) μeV. This mass value is compatible with the recent BICEP2 results and implies that Peccei-Quinn symmetry breaking was taking place after inflation.

  7. Globalization, commodification and mass transplant of nurses: Part 1.

    PubMed

    Cutcliffe, John R; Yarbrough, Susan

    The world is currently facing a shortage of nurses and this is predicted to worsen as a result of the looming en masse retirement of the so-called 'baby-boom' generation. Moreover, this problem is foreseen to be far more pronounced in Western countries where the post-Second World War 'baby-boom' demographic was (and is) most prominent. Data collected by various international organizations illustrates a corresponding recent increase in nurse migration and that such mass transplantation inevitably involves the unidirectional movement of nurses from developing countries to developed Western countries. As a result, this two-part article examines this mass transplantation within the context of globalization. Part one provides compelling international data regarding the global shortage of nurses and the corresponding increase in nurse migration from 'underdeveloped' to 'Western' countries. It then situates the phenomenon in the context of global health and highlights the extent of the debate so far, such as it is. PMID:17851350

  8. A global assessment of accelerations in surface mass transport

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoping; Heflin, Michael B.

    2015-08-01

    Water mass transport in the Earth's dynamic surface layer of atmosphere, cryosphere, and hydrosphere driven by various global change processes has complex spatiotemporal patterns. Here we determine global patterns and regional mean values of accelerations in surface mass variations during the Gravity Recovery and Climate Experiment (GRACE) mission's data span from 2002.2 to 2015.0. GRACE gravity data are supplemented by surface deformation from 607 Global Navigation Satellite System stations, an ocean bottom pressure model, satellite laser ranging, and loose a priori knowledge on mass variation regimes incorporating high-resolution geographic boundaries. While Greenland and West Antarctica have strong negative accelerations, Alaska and the Arctic Ocean show significant positive accelerations. In addition, the accelerations are not constant in time with some regions showing considerable variability due to irregular interannual changes. No evidence of significant nonsteric mean sea level acceleration has been found, but the uncertainty is quite large.

  9. Precise determination of earth's center of mass using measurements from the Global Positioning System

    NASA Technical Reports Server (NTRS)

    Vigue, Yvonne; Lichten, Stephen M.; Blewitt, Geoffrey; Heflin, Michael B.; Malla, Rajendra P.

    1992-01-01

    Global Positioning System (GPS) data from a worldwide geodetic experiment were collected during a 3-week period early in 1991. Geocentric station coordinates were estimated using the GPS data, thus defining a dynamically determined reference frame origin which should coincide with the earth center of mass, or geocenter. The 3-week GPS average geocenter estimates agree to 7-13 cm with geocenter estimates determined from satellite laser ranging, a well-established technique. The RMS of daily GPS geocenter estimates were 4 cm for x and y, and 30 cm for z.

  10. RSMASS: A simple model for estimating reactor and shield masses

    SciTech Connect

    Marshall, A.C.; Aragon, J.; Gallup, D.

    1987-01-01

    A simple mathematical model (RSMASS) has been developed to provide rapid estimates of reactor and shield masses for space-based reactor power systems. Approximations are used rather than correlations or detailed calculations to estimate the reactor fuel mass and the masses of the moderator, structure, reflector, pressure vessel, miscellaneous components, and the reactor shield. The fuel mass is determined either by neutronics limits, thermal/hydraulic limits, or fuel damage limits, whichever yields the largest mass. RSMASS requires the reactor power and energy, 24 reactor parameters, and 20 shield parameters to be specified. This parametric approach should be applicable to a very broad range of reactor types. Reactor and shield masses calculated by RSMASS were found to be in good agreement with the masses obtained from detailed calculations.

  11. Estimation of lipids and lean mass of migrating sandpipers

    USGS Publications Warehouse

    Skagen, Susan K.; Knopf, Fritz L.; Cade, Brian S.

    1993-01-01

    Estimation of lean mass and lipid levels in birds involves the derivation of predictive equations that relate morphological measurements and, more recently, total body electrical conductivity (TOBEC) indices to known lean and lipid masses. Using cross-validation techniques, we evaluated the ability of several published and new predictive equations to estimate lean and lipid mass of Semipalmated Sandpipers (Calidris pusilla) and White-rumped Sandpipers (C. fuscicollis). We also tested ideas of Morton et al. (1991), who stated that current statistical approaches to TOBEC methodology misrepresent precision in estimating body fat. Three published interspecific equations using TOBEC indices predicted lean and lipid masses of our sample of birds with average errors of 8-28% and 53-155%, respectively. A new two-species equation relating lean mass and TOBEC indices revealed average errors of 4.6% and 23.2% in predicting lean and lipid mass, respectively. New intraspecific equations that estimate lipid mass directly from body mass, morphological measurements, and TOBEC indices yielded about a 13% error in lipid estimates. Body mass and morphological measurements explained a substantial portion of the variance (about 90%) in fat mass of both species. Addition of TOBEC indices improved the predictive model more for the smaller than for the larger sandpiper. TOBEC indices explained an additional 7.8% and 2.6% of the variance in fat mass and reduced the minimum breadth of prediction intervals by 0.95 g (32%) and 0.39 g (13%) for Semipalmated and White-rumped Sandpipers, respectively. The breadth of prediction intervals for models used to predict fat levels of individual birds must be considered when interpreting the resultant lipid estimates.

  12. Global estimate of net annual carbon flow to phenylpropanoid metabolism

    SciTech Connect

    Walton, A.B.; Norman, E.G.; Turpin, D.H. )

    1993-05-01

    The steady increase in the concentration of CO[sub 2] in the atmosphere is the focus of renewed interest in the global carbon cycle. Current research is centered upon modeling the effects of the increasing CO[sub 2] concentrations, and thus global warning, on global plant homeostasis. It has been estimated that the annual net primary production (NPP) values for terrestrial and oceanic biomes are 59.9 and 35 Pg C-yr[sup [minus]1], respectively (Melillo et al., 1990). Based on these NPP values, we have estimated the annual C flow to phenlpropanoid metabolism. In our calculation, lignin was used as a surrogate for phenylpropanoid compounds, as lignin is the second most abundant plant polymer. This approach means that our estimate defines the lower limit of C flow to phenylpropanoid metabolism. Each biome was considered separately to determine the percent of the NPP which was directed to the biosynthesis of leaves, stems/branches, and roots. From published values of the lignin content of these organs, the total amount of C directed to the biosynthesis of lignin in each biome was determined. This was used to obtain a global value. Implications of these estimates will be discussed with reference to plant carbon and nitrogen metabolism.

  13. Estimating the true global burden of mental illness.

    PubMed

    Vigo, Daniel; Thornicroft, Graham; Atun, Rifat

    2016-02-01

    We argue that the global burden of mental illness is underestimated and examine the reasons for under-estimation to identify five main causes: overlap between psychiatric and neurological disorders; the grouping of suicide and self-harm as a separate category; conflation of all chronic pain syndromes with musculoskeletal disorders; exclusion of personality disorders from disease burden calculations; and inadequate consideration of the contribution of severe mental illness to mortality from associated causes. Using published data, we estimate the disease burden for mental illness to show that the global burden of mental illness accounts for 32·4% of years lived with disability (YLDs) and 13·0% of disability-adjusted life-years (DALYs), instead of the earlier estimates suggesting 21·2% of YLDs and 7·1% of DALYs. Currently used approaches underestimate the burden of mental illness by more than a third. Our estimates place mental illness a distant first in global burden of disease in terms of YLDs, and level with cardiovascular and circulatory diseases in terms of DALYs. The unacceptable apathy of governments and funders of global health must be overcome to mitigate the human, social, and economic costs of mental illness. PMID:26851330

  14. Global Building Inventory for Earthquake Loss Estimation and Risk Management

    USGS Publications Warehouse

    Jaiswal, Kishor; Wald, David; Porter, Keith

    2010-01-01

    We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat’s demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature.

  15. Inclination Dependence of Estimated Galaxy Masses and Star Formation Rates

    NASA Astrophysics Data System (ADS)

    Hernandez, Betsy; Maller, Ariyeh; McKernan, Barry; Ford, Saavik

    2016-01-01

    We examine the inclination dependence of inferred star formation rates and galaxy mass estimates in the Sloan Digital Sky Survey by combining the disk/bulge de-convolved catalog of Simard et al 2011 with stellar mass estimates catalog of Mendel et al 2014 and star formation rates measured from spectra by Brinchmann et al 2004. We know that optical star formation indicators are reddened by dust, but calculated star formation rates and stellar mass estimates should account for this. However, we find that face-on galaxies have a higher calculated average star formation rates than edge-on galaxies. We also find edge-on galaxies have ,on average, slightly smaller but similar estimated masses to face-on galaxies, suggesting that there are issues with the applied dust corrections for both models.

  16. Challenges and Approaches for Data Quality in Global Precipitation Estimation

    NASA Astrophysics Data System (ADS)

    Huffman, G. J.

    2011-12-01

    It is a substantial challenge to estimate the global distribution of precipitation at the finest scales because the retrieval problem is highly underdetermined, given the available satellite and surface data and the approximations that are needed to compute solutions. Sampling is improved by combining precipitation estimates from as many precipitation-relevant satellites as possible, but this step introduces the necessity of coping with differing retrieval capabilities from the various satellites. The usual response is to inter-calibrate the satellite estimates, usually choosing one satellite as a standard and performing histogram matching with coincident data for all the other satellites. Such matching requires numerous design decisions for practical use. As well, it has been shown that monthly accumulations of surface precipitation gauge data can be used to reduce bias and improve patterns of occurrence for monthly accumulations of satellite data, and short-interval satellite estimates can be improved with a simple scaling such that they sum to the monthly satellite-gauge combination. However, the quality of the short-interval estimates is still dominated by the random errors. Spatial and/or temporal averaging improve the random-error content of the estimates, although not the bias. This observation has a profound implication for the perceived utility of the precipitation data: applications that entail explicit or implicit averaging usually tolerate higher levels of random error than applications requiring skill in the full-resolution estimates. The presentation will consider some of the current issues confronting the analysis of error and quality for global precipitation. These include consideration of: how best to estimate the error for fine-scale precipitation estimates, particularly in areas where the precipitation estimate is zero; the impact of high- and low-end thresholds in estimators; and metrics that are appropriate to the fine-scale, discontinuous

  17. Further improvements on a global nuclear mass model

    SciTech Connect

    Liu Min; Wang Ning; Deng Yangge; Wu Xizhen

    2011-07-15

    The semi-empirical macroscopic-microscopic mass formula is further improved by considering some residual corrections. The rms deviation from 2149 known nuclear masses is significantly reduced to 336 keV, even lower than that achieved with the best of the Duflo-Zuker models. The {alpha}-decay energies of super-heavy nuclei, the Garvey-Kelson relations, and the isobaric multiplet mass equation (IMME) can be reproduced remarkably well with the model, and the predictive power of the mass model is good. With a systematic study of 17 global nuclear mass models, we find that the quadratic form of the IMME is closely related to the accuracy of nuclear mass calculations when the Garvey-Kelson relations are reproduced reasonably well. Fulfilling both the IMME and the Garvey-Kelson relations seem to be two necessary conditions for improving the quality of the model prediction. Furthermore, the {alpha}-decay energies of super-heavy nuclei should be used as an additional constraint on global nuclear mass models.

  18. Estimating impacts of lichens and bryophytes on global biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Porada, Philipp; Weber, Bettina; Elbert, Wolfgang; Pöschl, Ulrich; Kleidon, Axel

    2014-02-01

    Lichens and bryophytes may significantly affect global biogeochemical cycles by fixation of nitrogen and biotic enhancement of surface weathering rates. Most of the studies suggesting these effects, however, are either conceptual or rely on upscaling of regional estimates to obtain global numbers. Here we use a different method, based on estimates of net carbon uptake, to quantify the impacts of lichens and bryophytes on biogeochemical cycles at the global scale. We focus on three processes, namely, nitrogen fixation, phosphorus uptake, and chemical weathering. Our estimates have the form of potential rates, which means that we quantify the amount of nitrogen and phosphorus needed by the organisms to build up biomass, also accounting for resorption and leaching of nutrients. Subsequently, we use potential phosphorus uptake on bare ground to estimate chemical weathering by the organisms, assuming that they release weathering agents to obtain phosphorus. The predicted requirement for nitrogen ranges from 3.5 to 34 Tgyr-1 and for phosphorus it ranges from 0.46 to 4.6 Tgyr-1. Estimates of chemical weathering are between 0.058 and 1.1 km3 yr-1 of rock. These values seem to have a realistic order of magnitude, and they support the notion that lichens and bryophytes have the potential to play an important role for biogeochemical cycles.

  19. CALIBRATING C-IV-BASED BLACK HOLE MASS ESTIMATORS

    SciTech Connect

    Park, Daeseong; Woo, Jong-Hak; Shin, Jaejin; Denney, Kelly D. E-mail: woo@astro.snu.ac.kr E-mail: kelly@dark-cosmology.dk

    2013-06-20

    We present the single-epoch black hole mass estimators based on the C IV {lambda}1549 broad emission line, using the updated sample of the reverberation-mapped active galactic nuclei and high-quality UV spectra. By performing multi-component spectral fitting analysis, we measure the C IV line widths (FWHM{sub C{sub IV}} and line dispersion, {sigma}{sub C{sub IV}}) and the continuum luminosity at 1350 A (L{sub 1350}) to calibrate the C-IV-based mass estimators. By comparing with the H{beta} reverberation-based masses, we provide new mass estimators with the best-fit relationships, i.e., M{sub BH}{proportional_to}L{sub 1350}{sup 0.50{+-}0.07}{sigma}{sub C{sub IV}{sup 2}} and M{sub BH}{proportional_to}L{sub 1350}{sup 0.52{+-}0.09} FWHM{sub C{sub IV}{sup 0.56{+-}0.48}}. The new C-IV-based mass estimators show significant mass-dependent systematic difference compared to the estimators commonly used in the literature. Using the published Sloan Digital Sky Survey QSO catalog, we show that the black hole mass of high-redshift QSOs decreases on average by {approx}0.25 dex if our recipe is adopted.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Stacked Weak Lensing Mass Calibration: Estimators, Systematics, and Impact on Cosmological Parameter Constraints

    SciTech Connect

    Rozo, Eduardo; Wu, Hao-Yi; Schmidt, Fabian; /Caltech

    2011-11-04

    When extracting the weak lensing shear signal, one may employ either locally normalized or globally normalized shear estimators. The former is the standard approach when estimating cluster masses, while the latter is the more common method among peak finding efforts. While both approaches have identical signal-to-noise in the weak lensing limit, it is possible that higher order corrections or systematic considerations make one estimator preferable over the other. In this paper, we consider the efficacy of both estimators within the context of stacked weak lensing mass estimation in the Dark Energy Survey (DES). We find that the two estimators have nearly identical statistical precision, even after including higher order corrections, but that these corrections must be incorporated into the analysis to avoid observationally relevant biases in the recovered masses. We also demonstrate that finite bin-width effects may be significant if not properly accounted for, and that the two estimators exhibit different systematics, particularly with respect to contamination of the source catalog by foreground galaxies. Thus, the two estimators may be employed as a systematic cross-check of each other. Stacked weak lensing in the DES should allow for the mean mass of galaxy clusters to be calibrated to {approx}2% precision (statistical only), which can improve the figure of merit of the DES cluster abundance experiment by a factor of {approx}3 relative to the self-calibration expectation. A companion paper investigates how the two types of estimators considered here impact weak lensing peak finding efforts.

  2. Evaluation of Black Carbon Estimations in Global Aerosol Models

    SciTech Connect

    Koch, D.; Schulz, M.; Kinne, Stefan; McNaughton, C. S.; Spackman, J. R.; Balkanski, Y.; Bauer, S.; Berntsen, T.; Bond, Tami C.; Boucher, Olivier; Chin, M.; Clarke, A. D.; De Luca, N.; Dentener, F.; Diehl, T.; Dubovik, O.; Easter, Richard C.; Fahey, D. W.; Feichter, J.; Fillmore, D.; Freitag, S.; Ghan, Steven J.; Ginoux, P.; Gong, S.; Horowitz, L.; Iversen, T.; Kirkevag, A.; Klimont, Z.; Kondo, Yutaka; Krol, M.; Liu, Xiaohong; Miller, R.; Montanaro, V.; Moteki, N.; Myhre, G.; Penner, J.; Perlwitz, Ja; Pitari, G.; Reddy, S.; Sahu, L.; Sakamoto, H.; Schuster, G.; Schwarz, J. P.; Seland, O.; Stier, P.; Takegawa, Nobuyuki; Takemura, T.; Textor, C.; van Aardenne, John; Zhao, Y.

    2009-11-27

    range represented by the full set of AeroCom models. Upper tropospheric concentrations of BC mass from the aircraft measurements are suggested to provide a unique new benchmark to test scavenging and vertical dispersion of BC in global models.

  3. Space Geodesy Monitoring Mass Transport in Global Geophysical Fluids

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    2004-01-01

    Mass transports occurring in the atmosphere-hydrosphere-cryosphere-solid Earth-core system (the 'global geophysical fluids') are important geophysical phenomena. They occur on all temporal and spatial scales. Examples include air mass and ocean circulations, oceanic and solid tides, hydrological water and idsnow redistribution, mantle processes such as post-glacial rebound, earthquakes and tectonic motions, and core geodynamo activities. The temporal history and spatial pattern of such mass transport are often not amenable to direct observations. Space geodesy techniques, however, have proven to be an effective tool in monitorihg certain direct consequences of the mass transport, including Earth's rotation variations, gravitational field variations, and the geocenter motion. Considerable advances have been made in recent years in observing and understanding of these geodynamic effects. This paper will use several prominent examples to illustrate the triumphs in research over the past years under a 'Moore's law' in space geodesy. New space missions and projects promise to further advance our knowledge about the global mass transports. The latter contributes to our understanding of the geophysical processes that produce and regulate the mass transports, as well as of the solid Earth's response to such changes in terms of Earth's mechanical properties.

  4. Global Evapotranspiration Estimates using the Land Information System

    NASA Astrophysics Data System (ADS)

    Houser, P. R.; Peters-Lidard, C. D.; Rodell, M.

    2005-05-01

    The Global Land Data Assimilation System (GLDAS) is being used extensively by the research community for studies ranging from climate and weather forecast initialization to the improvement of hydrologic decision support systems. The goal of the GLDAS is to ingest satellite- and ground-based observational data products, using advanced land surface modeling and data assimilation techniques, in order to generate optimal fields of land surface states and fluxes (Rodell et al., 2004). The GLDAS software, which has been streamlined and parallelized by the Land Information System (LIS) software infrastructure, drives multiple, offline (not coupled to the atmosphere) land surface models, integrates a huge quantity of observation based data, executes on a global domain at high spatial resolutions (2.5° to 1 km), and is capable of producing results in near-real time. A vegetation-based "tiling" approach is used to simulate sub-grid scale variability, with a 1 km global vegetation dataset as its basis. Soil and elevation parameters are based on high-resolution global datasets. Observation-based precipitation and downward radiation products, as well as output fields from the best available global coupled atmospheric data assimilation systems, are employed to force the models. The international research community is using GLDAS to help assess global land surface conditions as part of the Global Energy and Water Cycle Experiment (GEWEX) Coordinated Enhanced Observing Period (CEOP), and GLDAS has been identified as NASA's land surface contribution to the Joint Center for Satellite Data Assimilation (JCSDA) enabling better use of remote sensing data in operational weather and climate forecasting. The global 1km resolution capability of LIS allows it to take advantage of the latest satellite observations, such as MODIS leaf area index and surface temperature, at their full resolution. In this presentation we will critically evaluate global LIS-based evapotranspiration estimates at

  5. Estimating the mass of mutagens in indeterminate mixtures

    SciTech Connect

    Schaeffer, D.J.; Kerster, H.W.

    1985-10-01

    A method is shown for estimating the quantity (mass) of genotoxic compounds in complex mixtures without prior identification of components. This method uses fractiles of the probability distribution of responses from the assay of interest and dose-response of the mixture. The method depends upon the assumption of additivity, on average, in the interaction of mutagens and on lognormality of the distribution of mutagen molecular weights. Mass estimates are necessary for hazard characterization, risk estimation, and risk assessment. The method is illustrated using Ames assay results from a coke plant wastewater.

  6. Estimated Global Mortality Attributable to Smoke from Landscape Fires

    PubMed Central

    Henderson, Sarah B.; Chen, Yang; Randerson, James T.; Marlier, Miriam; DeFries, Ruth S.; Kinney, Patrick; Bowman, David M.J.S.; Brauer, Michael

    2012-01-01

    Background: Forest, grass, and peat fires release approximately 2 petagrams of carbon into the atmosphere each year, influencing weather, climate, and air quality. Objective: We estimated the annual global mortality attributable to landscape fire smoke (LFS). Methods: Daily and annual exposure to particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5) from fire emissions was estimated globally for 1997 through 2006 by combining outputs from a chemical transport model with satellite-based observations of aerosol optical depth. In World Health Organization (WHO) subregions classified as sporadically affected, the daily burden of mortality was estimated using previously published concentration–response coefficients for the association between short-term elevations in PM2.5 from LFS (contrasted with 0 μg/m3 from LFS) and all-cause mortality. In subregions classified as chronically affected, the annual burden of mortality was estimated using the American Cancer Society study coefficient for the association between long-term PM2.5 exposure and all-cause mortality. The annual average PM2.5 estimates were contrasted with theoretical minimum (counterfactual) concentrations in each chronically affected subregion. Sensitivity of mortality estimates to different exposure assessments, counterfactual estimates, and concentration–response functions was evaluated. Strong La Niña and El Niño years were compared to assess the influence of interannual climatic variability. Results: Our principal estimate for the average mortality attributable to LFS exposure was 339,000 deaths annually. In sensitivity analyses the interquartile range of all tested estimates was 260,000–600,000. The regions most affected were sub-Saharan Africa (157,000) and Southeast Asia (110,000). Estimated annual mortality during La Niña was 262,000, compared with 532,000 during El Niño. Conclusions: Fire emissions are an important contributor to global mortality. Adverse health outcomes

  7. On optical mass estimation methods for galaxy groups

    NASA Astrophysics Data System (ADS)

    Pearson, R. J.; Ponman, T. J.; Norberg, P.; Robotham, A. S. G.; Farr, W. M.

    2015-05-01

    We examine the performance of a variety of different estimators for the mass of galaxy groups, based on their galaxy distribution alone. We draw galaxies from the Sloan Digital Sky Survey for a set of groups and clusters for which hydrostatic mass estimates based on high-quality Chandra X-ray data are available. These are used to calibrate the galaxy-based mass proxies, and to test their performance. Richness, luminosity, galaxy overdensity, rms radius and dynamical mass proxies are all explored. These different mass indicators all have their merits, and we argue that using them in combination can provide protection against being misled by the effects of dynamical disturbance or variations in star formation efficiency. Using them in this way leads us to infer the presence of significant non-statistical scatter in the X-ray based mass estimates we employ. We apply a similar analysis to a set of mock groups derived from applying a semi-analytic galaxy formation code to the Millennium dark matter simulation. The relations between halo mass and the mass proxies differ significantly in some cases from those seen in the observational groups, and we discuss possible reasons for this.

  8. Estimation of global anthropogenic dust aerosol using CALIOP satellite

    NASA Astrophysics Data System (ADS)

    Chen, B.; Huang, J.; Liu, J.

    2014-12-01

    Anthropogenic dust aerosols are those produced by human activity, which mainly come from cropland, pasture, and urban in this paper. Because understanding of the emissions of anthropogenic dust is still very limited, a new technique for separating anthropogenic dust from natural dustusing CALIPSO dust and planetary boundary layer height retrievalsalong with a land use dataset is introduced. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 22.3% of the global continentaldust load. Of these anthropogenic dust aerosols, more than 52.5% come from semi-arid and semi-wet regions. On the whole, anthropogenic dust emissions from East China and India are higher than other regions.

  9. Global estimates of boreal forest carbon stocks and flux

    NASA Astrophysics Data System (ADS)

    Bradshaw, Corey J. A.; Warkentin, Ian G.

    2015-05-01

    The boreal ecosystem is an important global reservoir of stored carbon and a haven for diverse biological communities. The natural disturbance dynamics there have historically been driven by fire and insects, with human-mediated disturbances increasing faster than in other biomes globally. Previous research on the total boreal carbon stock and predictions of its future flux reveal high uncertainty in regional patterns. We reviewed and standardised this extensive body of quantitative literature to provide the most up-to-date and comprehensive estimates of the global carbon balance in the boreal forest. We also compiled century-scale predictions of the carbon budget flux. Our review and standardisation confirmed high uncertainty in the available data, but there is evidence that the region's total carbon stock has been underestimated. We found a total carbon store of 367.3 to 1715.8 Pg (1015 g), the mid-point of which (1095 Pg) is between 1.3 and 3.8 times larger than any previous mean estimates. Most boreal carbon resides in its soils and peatlands, although estimates are highly uncertain. We found evidence that the region might become a net carbon source following a reduction in carbon uptake rate from at least the 1980s. Given that the boreal potentially constitutes the largest terrestrial carbon source in the world, in one of the most rapidly warming parts of the globe (Walsh, 2014), how we manage these stocks will be influential on future climate dynamics.

  10. Optimizing weak lensing mass estimates for cluster profile uncertainty

    SciTech Connect

    Gruen, D.; Bernstein, G. M.; Lam, T. Y.; Seitz, S.

    2011-09-11

    Weak lensing measurements of cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured cluster shear signal varies at fixed mass M200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight, and variations in the cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated halos to derive and evaluate a weak lensing circular aperture mass measurement Map that minimizes the mass estimate variance <(Map - M200m)2> in the presence of all these forms of variability. Depending on halo mass and observational conditions, the resulting mass estimator improves on Map filters optimized for circular NFW-profile clusters in the presence of uncorrelated large scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal cluster structure puts too much weight on the profile near the cores of halos, and under some circumstances can even be worse than not accounting for LSS at all. As a result, we discuss the impact of variability in cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate cluster MORs.

  11. Optimizing weak lensing mass estimates for cluster profile uncertainty

    DOE PAGESBeta

    Gruen, D.; Bernstein, G. M.; Lam, T. Y.; Seitz, S.

    2011-09-11

    Weak lensing measurements of cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured cluster shear signal varies at fixed mass M200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight, and variations in the cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated halos to derive and evaluate a weak lensing circular aperture mass measurement Map that minimizes the mass estimate variance <(Map - M200m)2> in the presence of all these forms of variability. Dependingmore » on halo mass and observational conditions, the resulting mass estimator improves on Map filters optimized for circular NFW-profile clusters in the presence of uncorrelated large scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal cluster structure puts too much weight on the profile near the cores of halos, and under some circumstances can even be worse than not accounting for LSS at all. As a result, we discuss the impact of variability in cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate cluster MORs.« less

  12. Estimation of gross primary production capacity from global satellite observations

    NASA Astrophysics Data System (ADS)

    Muramatsu, Kanako; Thanyapraneedkul, Juthasinee; Furumi, Shinobu; Soyama, Noriko; Daigo, Motomasa

    2012-10-01

    To estimate gross primary production (GPP), the process of photosynthesis was considered as two separate phases: capacity and reduction. The reduction phase is influenced by environmental conditions such as soil moisture and weather conditions such as vapor pressure differences. For a particular leaf, photosynthetic capacity mainly depends on the amount of chlorophyll and the RuBisCO enzyme. The chlorophyll content can be estimated by the color of the leaf, and leaf color can be detected by optical sensors. We used the chlorophyll content of leaves to estimate the level of GPP. A previously developed framework for GPP capacity estimation employs a chlorophyll index. The index is based on the linear relationship between the chlorophyll content of a leaf and the maximum photosynthesis at PAR =2000 (μmolm -2s-1) on a light-response curve under low stress conditions. As a first step, this study examined the global distribution of the index and found that regions with high chlorophyll index values in winter corresponded to tropical rainforest areas. The seasonal changes in the chlorophyll index differed from those shown by the normalized difference vegetation index. Next, the capacity of GPP was estimated from the light-response curve using the index. Most regions exhibited a higher GPP capacity than that estimated from Moderate Resolution Imaging Spectroradiometer (MODIS) observations, except in areas of tropical rainforest, where the GPP capacity and the MODIS GPP estimates were almost identical.

  13. A New Method for Deriving Global Estimates of Maternal Mortality.

    PubMed

    Wilmoth, John R; Mizoguchi, Nobuko; Oestergaard, Mikkel Z; Say, Lale; Mathers, Colin D; Zureick-Brown, Sarah; Inoue, Mie; Chou, Doris

    2012-07-13

    Maternal mortality is widely regarded as a key indicator of population health and of social and economic development. Its levels and trends are monitored closely by the United Nations and others, inspired in part by the UN's Millennium Development Goals (MDGs), which call for a three-fourths reduction in the maternal mortality ratio between 1990 and 2015. Unfortunately, the empirical basis for such monitoring remains quite weak, requiring the use of statistical models to obtain estimates for most countries. In this paper we describe a new method for estimating global levels and trends in maternal mortality. For countries lacking adequate data for direct calculation of estimates, we employed a parametric model that separates maternal deaths related to HIV/AIDS from all others. For maternal deaths unrelated to HIV/AIDS, the model consists of a hierarchical linear regression with three predictors and variable intercepts for both countries and regions. The uncertainty of estimates was assessed by simulating the estimation process, accounting for variability both in the data and in other model inputs. The method was used to obtain the most recent set of UN estimates, published in September 2010. Here, we provide a concise description and explanation of the approach, including a new analysis of the components of variability reflected in the uncertainty intervals. Final estimates provide evidence of a more rapid decline in the global maternal mortality ratio than suggested by previous work, including another study published in April 2010. We compare findings from the two recent studies and discuss topics for further research to help resolve differences. PMID:24416714

  14. A TRMM-Calibrated Infrared Technique for Global Rainfall Estimation

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Adler, Robert F.

    2002-01-01

    The development of a satellite infrared (IR) technique for estimating convective and stratiform rainfall and its application in studying the diurnal variability of rainfall on a global scale is presented. The Convective-Stratiform Technique (CST), calibrated by coincident, physically retrieved rain rates from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), is applied over the global tropics during 2001. The technique is calibrated separately over land and ocean, making ingenious use of the IR data from the TRMM Visible/Infrared Scanner (VIRS) before application to global geosynchronous satellite data. The low sampling rate of TRMM PR imposes limitations on calibrating IR-based techniques; however, our research shows that PR observations can be applied to improve IR-based techniques significantly by selecting adequate calibration areas and calibration length. The diurnal cycle of rainfall, as well as the division between convective and stratiform rainfall will be presented. The technique is validated using available data sets and compared to other global rainfall products such as Global Precipitation Climatology Project (GPCP) IR product, calibrated with TRMM Microwave Imager (TMI) data. The calibrated CST technique has the advantages of high spatial resolution (4 km), filtering of non-raining cirrus clouds, and the stratification of the rainfall into its convective and stratiform components, the latter being important for the calculation of vertical profiles of latent heating.

  15. A TRMM-Calibrated Infrared Technique for Global Rainfall Estimation

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Adler, Robert F.; Xu, Li-Ming

    2003-01-01

    This paper presents the development of a satellite infrared (IR) technique for estimating convective and stratiform rainfall and its application in studying the diurnal variability of rainfall on a global scale. The Convective-Stratiform Technique (CST), calibrated by coincident, physically retrieved rain rates from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), is applied over the global tropics during summer 2001. The technique is calibrated separately over land and ocean, making ingenious use of the IR data from the TRMM Visible/Infrared Scanner (VIRS) before application to global geosynchronous satellite data. The low sampling rate of TRMM PR imposes limitations on calibrating IR- based techniques; however, our research shows that PR observations can be applied to improve IR-based techniques significantly by selecting adequate calibration areas and calibration length. The diurnal cycle of rainfall, as well as the division between convective and t i f m rainfall will be presented. The technique is validated using available data sets and compared to other global rainfall products such as Global Precipitation Climatology Project (GPCP) IR product, calibrated with TRMM Microwave Imager (TMI) data. The calibrated CST technique has the advantages of high spatial resolution (4 km), filtering of non-raining cirrus clouds, and the stratification of the rainfall into its convective and stratiform components, the latter being important for the calculation of vertical profiles of latent heating.

  16. SAGE and SAM II measurements of global stratospheric aerosol optical depth and mass loading

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Mccormick, M. P.

    1984-01-01

    Several volcanic eruptions between November 1979 and April 1981 have injected material into the stratosphere. The SAGE and SAM II satellite systems have measured, with global coverage, the 1-micron extinction produced by this material, and examples of the data product are shown in the form of global maps of stratospheric optical depth and altitude-latitude plots of zonal mean extinction. These data, and that for the volcanically quiet period in early 1979, have been used to determine the changes in the total stratospheric mass loading. Estimates have also been made of the contribution to the total aerosol mass from each eruption. It has been found that between 1979 and mid-1981, the total stratospheric aerosol mass increased from a background level of approximately 570,000 metric tons to a peak of approximately 1,300,000 metric tons.

  17. A Global Estimate of the Number of Coral Reef Fishers

    PubMed Central

    Teh, Louise S. L.; Teh, Lydia C. L.; Sumaila, U. Rashid

    2013-01-01

    Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world’s small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale. PMID:23840327

  18. A Global Estimate of the Number of Coral Reef Fishers.

    PubMed

    Teh, Louise S L; Teh, Lydia C L; Sumaila, U Rashid

    2013-01-01

    Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world's small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale. PMID:23840327

  19. Estimates of mass and angular momentum in the oort cloud.

    PubMed

    Marochnik, L S; Mukhin, L M; Sagdeev, R Z

    1988-10-28

    Estimates can be made of unseen mass (in the form of cometary nuclei) at the heliocentric distances between 3 x 10(3) and 2 x 10(4) astronomical units(AU) under the assumptions (i) that the Oort cloud is a rarefied halo surrounding the core (dense, inner cometary cloud) and (ii) that the mass and albedo of comet Halley is typical for comets both in the core and the Oort cloud populations. The mass appears to be approximately 0.03 solar masses, with angular momentum of the order of 10(52) to 10(53) g-cm(2)/s. This mass is of the order of the total mass of the planetary system before the loss of volatiles. This leads to an estimate of a mass M(o) approximately 100 M( plus sign in circle) (where M( plus sign in circle) is the mass of Earth) concentrated in the Oort cloud (r > 2 x 10(4) AU) with an angular momentum that may exceed the present angular momentum of the whole planetary system by one order of magnitude. The present angular momentum of the Oort cloud appears to be of the same order as the total angular momentum of the planetary system before the loss of volatiles. PMID:17815893

  20. Atmospheric methyl bromide - Trends and global mass balance

    NASA Technical Reports Server (NTRS)

    Khalil, M. A. K.; Rasmussen, R. A.; Gunawardena, R.

    1993-01-01

    A decadal time series of global CH3Br concentrations in the earth's atmosphere is presented. It is shown that average concentrations are about 10 pptv and during the last 4 yr may be increasing at 0.3 +/- 0.1 pptv/yr. It is estimated that the atmospheric lifetime of CH3Br that is due to reaction with OH is about 2 yr, which results in a calculated global emission rate of about 100 Gg/yr. Ocean supersaturations of 140-180 percent are observed, and atmospheric concentrations over the open oceans are higher than at comparably located coastal sites. The ocean source is estimated to be about 35 Gg/yr. The remaining emissions must come from other natural sources and anthropogenic activities.

  1. Redefinition and global estimation of basal ecosystem respiration rate

    USGS Publications Warehouse

    Yuan, W.; Luo, Y.; Li, X.; Liu, S.; Yu, G.; Zhou, T.; Bahn, M.; Black, A.; Desai, A.R.; Cescatti, A.; Marcolla, B.; Jacobs, C.; Chen, J.; Aurela, M.; Bernhofer, C.; Gielen, B.; Bohrer, G.; Cook, D.R.; Dragoni, D.; Dunn, A.L.; Gianelle, D.; Grnwald, T.; Ibrom, A.; Leclerc, M.Y.; Lindroth, A.; Liu, H.; Marchesini, L.B.; Montagnani, L.; Pita, G.; Rodeghiero, M.; Rodrigues, A.; Starr, G.; Stoy, P.C.

    2011-01-01

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data, from 79 research sites located at latitudes ranging from ???3S to ???70N. Results showed that mean annual ER rate closely matches ER rate at mean annual temperature. Incorporation of site-specific BR into global ER model substantially improved simulated ER compared to an invariant BR at all sites. These results confirm that ER at the mean annual temperature can be considered as BR in empirical models. A strong correlation was found between the mean annual ER and mean annual gross primary production (GPP). Consequently, GPP, which is typically more accurately modeled, can be used to estimate BR. A light use efficiency GPP model (i.e., EC-LUE) was applied to estimate global GPP, BR and ER with input data from MERRA (Modern Era Retrospective-Analysis for Research and Applications) and MODIS (Moderate resolution Imaging Spectroradiometer). The global ER was 103 Pg C yr -1, with the highest respiration rate over tropical forests and the lowest value in dry and high-latitude areas. Copyright 2011 by the American Geophysical Union.

  2. Predictive Attitude Estimation Using Global Positioning System Signals

    NASA Technical Reports Server (NTRS)

    Crassidis, John L.; Markley, F. Landis; Lightsey, E. Glenn; Ketchum, Eleanor

    1997-01-01

    In this paper, a new algorithm is developed for attitude estimation using Global Positioning System (GPS) signals. The new algorithm is based on a predictive filtering scheme designed for spacecraft without rate measuring devices. The major advantage of this new algorithm over traditional Kalman filter approaches is that the model error is not assumed to represented by an unbiased Gaussian noise process with known covariance, but instead is determined during the estimation process. This is achieved by simultaneously solving system optimality conditions and an output error constraint. This approach is well suited for GPS attitude estimation since some error sources that contribute to attitude inaccuracy, such as signal multipath, are known to be non-Gaussian processes. Also, the predictive filter scheme can use either GPS signals or vector observations or a combination of both for attitude estimation, so that performance characteristics can be maintained during periods of GPS attitude sensor outage. The performance of the new algorithm is tested using flight data from the REX-2 spacecraft. Results are shown using the predictive filter to estimate the attitude from both GPS signals and magnetometer measurements, and comparing that solution to a magnetometer-only based solution. Results using the new estimation algorithm indicate that GPS-based solutions are verified to within 2 degrees using the magnetometer cross-check for the REX-2 spacecraft. GPS attitude accuracy of better than 1 degree is expected per axis, but cannot be reliably proven due to inaccuracies in the magnetic field model.

  3. Progress toward Consensus Estimates of Regional Glacier Mass Balances for IPCC AR5

    NASA Astrophysics Data System (ADS)

    Arendt, A. A.; Gardner, A. S.; Cogley, J. G.

    2011-12-01

    Glaciers are potentially large contributors to rising sea level. Since the last IPCC report in 2007 (AR4), there has been a widespread increase in the use of geodetic observations from satellite and airborne platforms to complement field observations of glacier mass balance, as well as significant improvements in the global glacier inventory. Here we summarize our ongoing efforts to integrate data from multiple sources to arrive at a consensus estimate for each region, and to quantify uncertainties in those estimates. We will use examples from Alaska to illustrate methods for combining Gravity Recovery and Climate Experiment (GRACE), elevation differencing and field observations into a single time series with related uncertainty estimates. We will pay particular attention to reconciling discrepancies between GRACE estimates from multiple processing centers. We will also investigate the extent to which improvements in the glacier inventory affect the accuracy of our regional mass balances.

  4. TRMM: Status of Precipitation Estimates, Science Highlights, and 3-Hour Global, Tropical Precipitation Estimates

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The Tropical Rainfall Measuring Mission (TRMM) has completed more than three years in orbit. A summary of research highlights will be presented focusing on application of TRMM data to topics ranging from climate analysis, through improving forecasts, to microphysical research. Examples and plans for operational use of TRMM data in tropical cyclone and other applications will be given. The status of precipitation estimates from different instruments and algorithms will be described. Monthly surface rainfall estimates over the ocean based on different instruments on TRMM currently differ by 20% in overall mean. In addition, time changes in global ocean rainfall between El Nino and La Nina conditions show a difference in sign between the active and passive microwave products. These differences are not surprising considering the different type of observations available for the first time from TRMM with both the passive and active microwave sensors. Resolving the differences will strengthen the validity and utility of ocean rainfall estimates. The TRMM rainfall estimates are intercompared among themselves and with other estimates, including those of the standard, monthly Global Precipitation Climatology Project (GPCP) analysis. The GPCP analysis agrees roughly in magnitude with the passive microwave-based TRMM estimates which is not surprising considering GPCP over-ocean estimates are based on passive microwave observations. A three-year TRMM rainfall climatology is presented, including anomaly fields related to the changing ENSO situation during the mission. Results of using TRMM information to calibrate other passive microwave observations and geosynchronous infrared rainfall estimates and then merging them those estimates into a global, tropical 3-hour time resolution analysis will also be described.

  5. Brief Communication: Global reconstructions of glacier mass change during the 20th century are consistent

    NASA Astrophysics Data System (ADS)

    Marzeion, B.; Leclercq, P. W.; Cogley, J. G.; Jarosch, A. H.

    2015-12-01

    Recent estimates of the contribution of glaciers to sea-level rise during the 20th century are strongly divergent. Advances in data availability have allowed revisions of some of these published estimates. Here we show that outside of Antarctica, the global estimates of glacier mass change obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other, and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist in estimates on regional scales.

  6. Brief Communication: Global glacier mass loss reconstructions during the 20th century are consistent

    NASA Astrophysics Data System (ADS)

    Marzeion, B.; Leclercq, P. W.; Cogley, J. G.; Jarosch, A. H.

    2015-07-01

    Estimates of the contribution of glaciers to sea-level rise during the 20th century that were published in recent years are strongly divergent. Advances in data availability have allowed revisions of some of these published estimates. Here we show that outside of Antarctica, the global estimates of glacier mass loss obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other, and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist in estimates on regional scales.

  7. Estimating maximum global wind power availability and associated climatic consequences

    NASA Astrophysics Data System (ADS)

    Miller, Lee; Gans, Fabian; Kleidon, Axel

    2010-05-01

    Estimating maximum global wind power availability and associated climatic consequences Wind speed reflects the continuous generation of kinetic energy and its dissipation, primarily in the atmospheric boundary layer. When wind turbines extract kinetic wind energy, less kinetic energy remains in the atmosphere in the mean state. While this effect does not play a significant role for a single turbine, it becomes a critical factor for the estimation of large-scale wind power availability. This extraction of kinetic energy by turbines also competes with the natural processes of kinetic energy dissipation, thus setting fundamental limits on extractability that are not considered in previous large-scale studies [1,2,3]. Our simple momentum balance model using ECMWF climate data illustrates a fundamental limit to global wind power extractability and thereby electricity potential (93TW). This is independent of engineering advances in turbine design and wind farm layout. These results are supported by similar results using a global climate model of intermediate complexity. Varying the surface drag coefficient with different simulations allows us to directly relate changes in atmospheric and boundary layer dissipation with resulting climate indices and wind power potential. These new estimates of the maximum power generation by wind turbines are well above the currently installed capacity. Hence, present day installations are unlikely to have a global impact. However, when compared to the current human energy demand of 17TW combined with plans by the US and EU to drastically increase onshore and offshore wind turbine installations [4,5,6], understanding the climatic response and ultimate limitations of wind power as a large-scale renewable energy source is critical. [1] Archer, C., and M.Z. Jacobson, (2005) Evaluation of global wind power, J. Geophys. Res. 110:D12110. [2] Lu, X., M.B. McElroy, and J. Kiviluoma, (2009) Global potential for wind-generated electricity, Proc

  8. Mass storage estimates for the digital mapping era.

    USGS Publications Warehouse

    Light, D.L.

    1986-01-01

    Proponents of the digital era recognize that a break-through in mass storage technology may be required to attain a reasonable degree of computerization of the cartographic mapping and data management process. This paper provides the rationale for estimating that about 1014 bits of digital mass storage are needed for developing a digital 1:24 000-scale topographic data base of the US. Also, it will discuss the optical disk as a leading candidate for handling the mass storage dilemma.-from Author

  9. Convex-hull mass estimates of the dodo (Raphus cucullatus): application of a CT-based mass estimation technique

    PubMed Central

    O’Mahoney, Thomas G.; Kitchener, Andrew C.; Manning, Phillip L.; Sellers, William I.

    2016-01-01

    The external appearance of the dodo (Raphus cucullatus, Linnaeus, 1758) has been a source of considerable intrigue, as contemporaneous accounts or depictions are rare. The body mass of the dodo has been particularly contentious, with the flightless pigeon alternatively reconstructed as slim or fat depending upon the skeletal metric used as the basis for mass prediction. Resolving this dichotomy and obtaining a reliable estimate for mass is essential before future analyses regarding dodo life history, physiology or biomechanics can be conducted. Previous mass estimates of the dodo have relied upon predictive equations based upon hind limb dimensions of extant pigeons. Yet the hind limb proportions of dodo have been found to differ considerably from those of their modern relatives, particularly with regards to midshaft diameter. Therefore, application of predictive equations to unusually robust fossil skeletal elements may bias mass estimates. We present a whole-body computed tomography (CT) -based mass estimation technique for application to the dodo. We generate 3D volumetric renders of the articulated skeletons of 20 species of extant pigeons, and wrap minimum-fit ‘convex hulls’ around their bony extremities. Convex hull volume is subsequently regressed against mass to generate predictive models based upon whole skeletons. Our best-performing predictive model is characterized by high correlation coefficients and low mean squared error (a = − 2.31, b = 0.90, r2 = 0.97, MSE = 0.0046). When applied to articulated composite skeletons of the dodo (National Museums Scotland, NMS.Z.1993.13; Natural History Museum, NHMUK A.9040 and S/1988.50.1), we estimate eviscerated body masses of 8–10.8 kg. When accounting for missing soft tissues, this may equate to live masses of 10.6–14.3 kg. Mass predictions presented here overlap at the lower end of those previously published, and support recent suggestions of a relatively slim dodo. CT-based reconstructions provide a

  10. Estimation of global snow cover using passive microwave data

    NASA Astrophysics Data System (ADS)

    Chang, Alfred T. C.; Kelly, Richard E.; Foster, James L.; Hall, Dorothy K.

    2003-04-01

    This paper describes an approach to estimate global snow cover using satellite passive microwave data. Snow cover is detected using the high frequency scattering signal from natural microwave radiation, which is observed by passive microwave instruments. Developed for the retrieval of global snow depth and snow water equivalent using Advanced Microwave Scanning Radiometer EOS (AMSR-E), the algorithm uses passive microwave radiation along with a microwave emission model and a snow grain growth model to estimate snow depth. The microwave emission model is based on the Dense Media Radiative Transfer (DMRT) model that uses the quasi-crystalline approach and sticky particle theory to predict the brightness temperature from a single layered snowpack. The grain growth model is a generic single layer model based on an empirical approach to predict snow grain size evolution with time. Gridding to the 25 km EASE-grid projection, a daily record of Special Sensor Microwave Imager (SSM/I) snow depth estimates was generated for December 2000 to March 2001. The estimates are tested using ground measurements from two continental-scale river catchments (Nelson River and the Ob River in Russia). This regional-scale testing of the algorithm shows that for passive microwave estimates, the average daily snow depth retrieval standard error between estimated and measured snow depths ranges from 0 cm to 40 cm of point observations. Bias characteristics are different for each basin. A fraction of the error is related to uncertainties about the grain growth initialization states and uncertainties about grain size changes through the winter season that directly affect the parameterization of the snow depth estimation in the DMRT model. Also, the algorithm does not include a correction for forest cover and this effect is clearly observed in the retrieval. Finally, error is also related to scale differences between in situ ground measurements and area-integrated satellite estimates. With AMSR

  11. Approaches and Data Quality for Global Precipitation Estimation

    NASA Astrophysics Data System (ADS)

    Huffman, G. J.; Bolvin, D. T.; Nelkin, E. J.

    2015-12-01

    The space and time scales on which precipitation varies are small compared to the satellite coverage that we have, so it is necessary to merge "all" of the available satellite estimates. Differing retrieval capabilities from the various satellites require inter-calibration for the satellite estimates, while "morphing", i.e., Lagrangian time interpolation, is used to lengthen the period over which time interpolation is valid. Additionally, estimates from geostationary-Earth-orbit infrared data are plentiful, but of sufficiently lower quality compared to low-Earth-orbit passive microwave estimates that they are only used when needed. Finally, monthly surface precipitation gauge data can be used to reduce bias and improve patterns of occurrence for monthly satellite data, and short-interval satellite estimates can be improved with a simple scaling such that they sum to the monthly satellite-gauge combination. The presentation will briefly consider some of the design decisions for practical computation of the Global Precipitation Measurement (GPM) mission product Integrated Multi-satellitE Retrievals for GPM (IMERG), then examine design choices that maximize value for end users. For example, data fields are provided in the output file that provide insight into the basis for the estimated precipitation, including error, sensor providing the estimate, precipitation phase (solid/liquid), and intermediate precipitation estimates. Another important initiative is successive computations for the same data date/time at longer latencies as additional data are received, which for IMERG is currently done at 6 hours, 16 hours, and 3 months after observation time. Importantly, users require long records for each latency, which runs counter to the data archiving practices at most archive sites. As well, the assignment of Digital Object Identifiers (DOI's) for near-real-time data sets (at 6 and 16 hours for IMERG) is not a settled issue.

  12. Global Rotation Estimation Using Weighted Iterative Lie Algebraic Averaging

    NASA Astrophysics Data System (ADS)

    Reich, M.; Heipke, C.

    2015-08-01

    In this paper we present an approach for a weighted rotation averaging to estimate absolute rotations from relative rotations between two images for a set of multiple overlapping images. The solution does not depend on initial values for the unknown parameters and is robust against outliers. Our approach is one part of a solution for a global image orientation. Often relative rotations are not free from outliers, thus we use the redundancy in available pairwise relative rotations and present a novel graph-based algorithm to detect and eliminate inconsistent rotations. The remaining relative rotations are input to a weighted least squares adjustment performed in the Lie algebra of the rotation manifold SO(3) to obtain absolute orientation parameters for each image. Weights are determined using the prior information we derived from the estimation of the relative rotations. Because we use the Lie algebra of SO(3) for averaging no subsequent adaptation of the results has to be performed but the lossless projection to the manifold. We evaluate our approach on synthetic and real data. Our approach often is able to detect and eliminate all outliers from the relative rotations even if very high outlier rates are present. We show that we improve the quality of the estimated absolute rotations by introducing individual weights for the relative rotations based on various indicators. In comparison with the state-of-the-art in recent publications to global image orientation we achieve best results in the examined datasets.

  13. Global parameter estimation for thermodynamic models of transcriptional regulation.

    PubMed

    Suleimenov, Yerzhan; Ay, Ahmet; Samee, Md Abul Hassan; Dresch, Jacqueline M; Sinha, Saurabh; Arnosti, David N

    2013-07-15

    Deciphering the mechanisms involved in gene regulation holds the key to understanding the control of central biological processes, including human disease, population variation, and the evolution of morphological innovations. New experimental techniques including whole genome sequencing and transcriptome analysis have enabled comprehensive modeling approaches to study gene regulation. In many cases, it is useful to be able to assign biological significance to the inferred model parameters, but such interpretation should take into account features that affect these parameters, including model construction and sensitivity, the type of fitness calculation, and the effectiveness of parameter estimation. This last point is often neglected, as estimation methods are often selected for historical reasons or for computational ease. Here, we compare the performance of two parameter estimation techniques broadly representative of local and global approaches, namely, a quasi-Newton/Nelder-Mead simplex (QN/NMS) method and a covariance matrix adaptation-evolutionary strategy (CMA-ES) method. The estimation methods were applied to a set of thermodynamic models of gene transcription applied to regulatory elements active in the Drosophila embryo. Measuring overall fit, the global CMA-ES method performed significantly better than the local QN/NMS method on high quality data sets, but this difference was negligible on lower quality data sets with increased noise or on data sets simplified by stringent thresholding. Our results suggest that the choice of parameter estimation technique for evaluation of gene expression models depends both on quality of data, the nature of the models [again, remains to be established] and the aims of the modeling effort. PMID:23726942

  14. Global positioning system watches for estimating energy expenditure.

    PubMed

    Hongu, Nobuko; Orr, Barron J; Roe, Denise J; Reed, Rebecca G; Going, Scott B

    2013-11-01

    Global positioning system (GPS) watches have been introduced commercially, converting frequent measurements of time, location, speed (pace), and elevation into energy expenditure (EE) estimates. The purpose of this study was to compare EE estimates of 4 different GPS watches (Forerunner, Suunto, Polar, Adeo), at various walking speeds, with EE estimate from a triaxial accelerometer (RT3), which was used as a reference measure in this study. Sixteen healthy young adults completed the study. Participants wore 4 different GPS watches and an RT3 accelerometer and walked at 6-minute intervals on an outdoor track at 3 speeds (3, 5, and 7 km/hr). The statistical significance of differences in EE between the 3 watches was assessed using linear contrasts of the coefficients from the overall model. Reliability across trials for a given device was assessed using intraclass correlation coefficients as estimated in the mixed model. The GPS watches demonstrated lower reliability (intraclass correlation coefficient) across trials when compared with the RT3, particularly at the higher speed, 7 km/hr. Three GPS watches (Forerunner, Polar, and Suunto) significantly and consistently underestimated EE compared with the reference EE given by the RT3 accelerometer (average mean difference: Garmin, -50.5%; Polar, -41.7%; and Suunto, -41.7%; all p < 0.001). Results suggested that caution should be exercised when using commercial GPS watches to estimate EE in athletes during field-based testing and training. PMID:23439338

  15. Body mass estimates of an exceptionally complete Stegosaurus (Ornithischia: Thyreophora): comparing volumetric and linear bivariate mass estimation methods

    PubMed Central

    Brassey, Charlotte A.; Maidment, Susannah C. R.; Barrett, Paul M.

    2015-01-01

    Body mass is a key biological variable, but difficult to assess from fossils. Various techniques exist for estimating body mass from skeletal parameters, but few studies have compared outputs from different methods. Here, we apply several mass estimation methods to an exceptionally complete skeleton of the dinosaur Stegosaurus. Applying a volumetric convex-hulling technique to a digital model of Stegosaurus, we estimate a mass of 1560 kg (95% prediction interval 1082–2256 kg) for this individual. By contrast, bivariate equations based on limb dimensions predict values between 2355 and 3751 kg and require implausible amounts of soft tissue and/or high body densities. When corrected for ontogenetic scaling, however, volumetric and linear equations are brought into close agreement. Our results raise concerns regarding the application of predictive equations to extinct taxa with no living analogues in terms of overall morphology and highlight the sensitivity of bivariate predictive equations to the ontogenetic status of the specimen. We emphasize the significance of rare, complete fossil skeletons in validating widely applied mass estimation equations based on incomplete skeletal material and stress the importance of accurately determining specimen age prior to further analyses. PMID:25740841

  16. Body mass estimates of an exceptionally complete Stegosaurus (Ornithischia: Thyreophora): comparing volumetric and linear bivariate mass estimation methods.

    PubMed

    Brassey, Charlotte A; Maidment, Susannah C R; Barrett, Paul M

    2015-03-01

    Body mass is a key biological variable, but difficult to assess from fossils. Various techniques exist for estimating body mass from skeletal parameters, but few studies have compared outputs from different methods. Here, we apply several mass estimation methods to an exceptionally complete skeleton of the dinosaur Stegosaurus. Applying a volumetric convex-hulling technique to a digital model of Stegosaurus, we estimate a mass of 1560 kg (95% prediction interval 1082-2256 kg) for this individual. By contrast, bivariate equations based on limb dimensions predict values between 2355 and 3751 kg and require implausible amounts of soft tissue and/or high body densities. When corrected for ontogenetic scaling, however, volumetric and linear equations are brought into close agreement. Our results raise concerns regarding the application of predictive equations to extinct taxa with no living analogues in terms of overall morphology and highlight the sensitivity of bivariate predictive equations to the ontogenetic status of the specimen. We emphasize the significance of rare, complete fossil skeletons in validating widely applied mass estimation equations based on incomplete skeletal material and stress the importance of accurately determining specimen age prior to further analyses. PMID:25740841

  17. A New Method to Estimate Halo Mass of Galaxy Groups

    NASA Astrophysics Data System (ADS)

    Lu, Yi; Yang, Xiaohu; Shen, Shiyin

    2015-08-01

    Reliable halo mass estimation for a given galaxy system plays an important role both in cosmology and galaxy formation studies. Here we set out to find the way that can improve the halo mass estimation for those galaxy systems with limited brightest member galaxies been observed. Using four mock galaxy samples constructed from semi-analytical formation models, the subhalo abundance matching method and the conditional luminosity functions, respectively, we find that the luminosity gap between the brightest and the subsequent brightest member galaxies in a halo (group) can be used to significantly reduce the scatter in the halo mass estimation based on the luminosity of the brightest galaxy alone. Tests show that these corrections can significantly reduce the scatter in the halo mass estimations by $\\sim 50\\%$ to $\\sim 70\\%$ in massive halos depending on which member galaxies are considered. Comparing to the traditional ranking method, we find that this method works better for groups with less than five members, or in observations with very bright magnitude cut.

  18. Nitrogen trifluoride global emissions estimated from updated atmospheric measurements

    PubMed Central

    Arnold, Tim; Harth, Christina M.; Mühle, Jens; Manning, Alistair J.; Salameh, Peter K.; Kim, Jooil; Ivy, Diane J.; Steele, L. Paul; Petrenko, Vasilii V.; Severinghaus, Jeffrey P.; Baggenstos, Daniel; Weiss, Ray F.

    2013-01-01

    Nitrogen trifluoride (NF3) has potential to make a growing contribution to the Earth’s radiative budget; however, our understanding of its atmospheric burden and emission rates has been limited. Based on a revision of our previous calibration and using an expanded set of atmospheric measurements together with an atmospheric model and inverse method, we estimate that the global emissions of NF3 in 2011 were 1.18 ± 0.21 Gg⋅y−1, or ∼20 Tg CO2-eq⋅y−1 (carbon dioxide equivalent emissions based on a 100-y global warming potential of 16,600 for NF3). The 2011 global mean tropospheric dry air mole fraction was 0.86 ± 0.04 parts per trillion, resulting from an average emissions growth rate of 0.09 Gg⋅y−2 over the prior decade. In terms of CO2 equivalents, current NF3 emissions represent between 17% and 36% of the emissions of other long-lived fluorinated compounds from electronics manufacture. We also estimate that the emissions benefit of using NF3 over hexafluoroethane (C2F6) in electronics manufacture is significant—emissions of between 53 and 220 Tg CO2-eq⋅y−1 were avoided during 2011. Despite these savings, total NF3 emissions, currently ∼10% of production, are still significantly larger than expected assuming global implementation of ideal industrial practices. As such, there is a continuing need for improvements in NF3 emissions reduction strategies to keep pace with its increasing use and to slow its rising contribution to anthropogenic climate forcing. PMID:23341630

  19. Global Solutions of the Boltzmann Equation Over {{R}^D} Near Global Maxwellians with Small Mass

    NASA Astrophysics Data System (ADS)

    Bardos, Claude; Gamba, Irene M.; Golse, François; Levermore, C. David

    2016-07-01

    We study the dynamics defined by the Boltzmann equation set in the Euclidean space {{R}^D} in the vicinity of global Maxwellians with finite mass. A global Maxwellian is a special solution of the Boltzmann equation for which the collision integral vanishes identically. In this setting, the dispersion due to the advection operator quenches the dissipative effect of the Boltzmann collision integral. As a result, the large time limit of solutions of the Boltzmann equation in this regime is given by noninteracting, freely transported states and can be described with the tools of scattering theory.

  20. Estimating Mass of Inflatable Aerodynamic Decelerators Using Dimensionless Parameters

    NASA Technical Reports Server (NTRS)

    Samareh, Jamshid A.

    2011-01-01

    This paper describes a technique for estimating mass for inflatable aerodynamic decelerators. The technique uses dimensional analysis to identify a set of dimensionless parameters for inflation pressure, mass of inflation gas, and mass of flexible material. The dimensionless parameters enable scaling of an inflatable concept with geometry parameters (e.g., diameter), environmental conditions (e.g., dynamic pressure), inflation gas properties (e.g., molecular mass), and mass growth allowance. This technique is applicable for attached (e.g., tension cone, hypercone, and stacked toroid) and trailing inflatable aerodynamic decelerators. The technique uses simple engineering approximations that were developed by NASA in the 1960s and 1970s, as well as some recent important developments. The NASA Mars Entry and Descent Landing System Analysis (EDL-SA) project used this technique to estimate the masses of the inflatable concepts that were used in the analysis. The EDL-SA results compared well with two independent sets of high-fidelity finite element analyses.

  1. Estimating global chlorophyll changes over the past century

    NASA Astrophysics Data System (ADS)

    Boyce, Daniel G.; Dowd, Michael; Lewis, Marlon R.; Worm, Boris

    2014-03-01

    Marine phytoplankton account for approximately half of the production of organic matter on earth, support virtually all marine ecosystems, constrain fisheries yields, and influence climate and weather. Despite this importance, long-term trajectories of phytoplankton abundance or biomass are difficult to estimate, and the extent of changes is unresolved. Here, we use a new, publicly-available database of historical shipboard oceanographic measurements to estimate long-term changes in chlorophyll concentration (Chl; a widely used proxy for phytoplankton biomass) from 1890 to 2010. This work builds upon an earlier analysis (Boyce et al., 2010) by taking published criticisms into account, and by using recalibrated data, and novel analysis methods. Rates of long-term chlorophyll change were estimated using generalized additive models within a multi-model inference framework, and post hoc sensitivity analyses were undertaken to test the robustness of results. Our analysis revealed statistically significant Chl declines over 62% of the global ocean surface area where data were present, and in 8 of 11 large ocean regions. While Chl increases have occurred in many locations, weighted syntheses of local- and regional-scale estimates confirmed that average chlorophyll concentrations have declined across the majority of the global ocean area over the past century. Sensitivity analyses indicate that these changes do not arise from any bias between data types, nor do they depend upon the method of spatial or temporal aggregation, nor the use of a particular statistical model. The wider consequences of this long-term decline of marine phytoplankton are presently unresolved, but will need to be considered in future studies of marine ecosystem structure, geochemical cycling, and fishery yields.

  2. Estimating the Global Burden of Endemic Canine Rabies

    PubMed Central

    Hampson, Katie; Coudeville, Laurent; Lembo, Tiziana; Sambo, Maganga; Kieffer, Alexia; Attlan, Michaël; Barrat, Jacques; Blanton, Jesse D.; Briggs, Deborah J.; Cleaveland, Sarah; Costa, Peter; Freuling, Conrad M.; Hiby, Elly; Knopf, Lea; Leanes, Fernando; Meslin, François-Xavier; Metlin, Artem; Miranda, Mary Elizabeth; Müller, Thomas; Nel, Louis H.; Recuenco, Sergio; Rupprecht, Charles E.; Schumacher, Carolin; Taylor, Louise; Vigilato, Marco Antonio Natal; Zinsstag, Jakob; Dushoff, Jonathan

    2015-01-01

    Background Rabies is a notoriously underreported and neglected disease of low-income countries. This study aims to estimate the public health and economic burden of rabies circulating in domestic dog populations, globally and on a country-by-country basis, allowing an objective assessment of how much this preventable disease costs endemic countries. Methodology/Principal Findings We established relationships between rabies mortality and rabies prevention and control measures, which we incorporated into a model framework. We used data derived from extensive literature searches and questionnaires on disease incidence, control interventions and preventative measures within this framework to estimate the disease burden. The burden of rabies impacts on public health sector budgets, local communities and livestock economies, with the highest risk of rabies in the poorest regions of the world. This study estimates that globally canine rabies causes approximately 59,000 (95% Confidence Intervals: 25-159,000) human deaths, over 3.7 million (95% CIs: 1.6-10.4 million) disability-adjusted life years (DALYs) and 8.6 billion USD (95% CIs: 2.9-21.5 billion) economic losses annually. The largest component of the economic burden is due to premature death (55%), followed by direct costs of post-exposure prophylaxis (PEP, 20%) and lost income whilst seeking PEP (15.5%), with only limited costs to the veterinary sector due to dog vaccination (1.5%), and additional costs to communities from livestock losses (6%). Conclusions/Significance This study demonstrates that investment in dog vaccination, the single most effective way of reducing the disease burden, has been inadequate and that the availability and affordability of PEP needs improving. Collaborative investments by medical and veterinary sectors could dramatically reduce the current large, and unnecessary, burden of rabies on affected communities. Improved surveillance is needed to reduce uncertainty in burden estimates and to

  3. Mass support for global climate agreements depends on institutional design.

    PubMed

    Bechtel, Michael M; Scheve, Kenneth F

    2013-08-20

    Effective climate mitigation requires international cooperation, and these global efforts need broad public support to be sustainable over the long run. We provide estimates of public support for different types of climate agreements in France, Germany, the United Kingdom, and the United States. Using data from a large-scale experimental survey, we explore how three key dimensions of global climate cooperation--costs and distribution, participation, and enforcement--affect individuals' willingness to support these international efforts. We find that design features have significant effects on public support. Specifically, our results indicate that support is higher for global climate agreements that involve lower costs, distribute costs according to prominent fairness principles, encompass more countries, and include a small sanction if a country fails to meet its emissions reduction targets. In contrast to well-documented baseline differences in public support for climate mitigation efforts, opinion responds similarly to changes in climate policy design in all four countries. We also find that the effects of institutional design features can bring about decisive changes in the level of public support for a global climate agreement. Moreover, the results appear consistent with the view that the sensitivity of public support to design features reflects underlying norms of reciprocity and individuals' beliefs about the potential effectiveness of specific agreements. PMID:23886666

  4. Mass support for global climate agreements depends on institutional design

    PubMed Central

    Bechtel, Michael M.; Scheve, Kenneth F.

    2013-01-01

    Effective climate mitigation requires international cooperation, and these global efforts need broad public support to be sustainable over the long run. We provide estimates of public support for different types of climate agreements in France, Germany, the United Kingdom, and the United States. Using data from a large-scale experimental survey, we explore how three key dimensions of global climate cooperation—costs and distribution, participation, and enforcement—affect individuals’ willingness to support these international efforts. We find that design features have significant effects on public support. Specifically, our results indicate that support is higher for global climate agreements that involve lower costs, distribute costs according to prominent fairness principles, encompass more countries, and include a small sanction if a country fails to meet its emissions reduction targets. In contrast to well-documented baseline differences in public support for climate mitigation efforts, opinion responds similarly to changes in climate policy design in all four countries. We also find that the effects of institutional design features can bring about decisive changes in the level of public support for a global climate agreement. Moreover, the results appear consistent with the view that the sensitivity of public support to design features reflects underlying norms of reciprocity and individuals’ beliefs about the potential effectiveness of specific agreements. PMID:23886666

  5. Global Water Resources Under Future Changes: Toward an Improved Estimation

    NASA Astrophysics Data System (ADS)

    Islam, M.; Agata, Y.; Hanasaki, N.; Kanae, S.; Oki, T.

    2005-05-01

    Global water resources availability in the 21st century is going to be an important concern. Despite its international recognition, however, until now there are very limited global estimates of water resources, which considered the geographical linkage between water supply and demand, defined by runoff and its passage through river network. The available studies are again insufficient due to reasons like different approaches in defining water scarcity, simply based on annual average figures without considering the inter-annual or seasonal variability, absence of the inclusion of virtual water trading, etc. In this study, global water resources under future climate change associated with several socio-economic factors were estimated varying over both temporal and spatial scale. Global runoff data was derived from several land surface models under the GSWP2 (Global Soil Wetness Project) project, which was further processed through TRIP (Total Runoff Integrated Pathways) river routing model to produce a 0.5x0.5 degree grid based figure. Water abstraction was estimated for the same spatial resolution for three sectors as domestic, industrial and agriculture. GCM outputs from CCSR and MRI were collected to predict the runoff changes. Socio-economic factors like population and GDP growth, affected mostly the demand part. Instead of simply looking at annual figures, monthly figures for both supply and demand was considered. For an average year, such a seasonal variability can affect the crop yield significantly. In other case, inter-annual variability of runoff can cause for an absolute drought condition. To account for vulnerabilities of a region to future changes, both inter-annual and seasonal effects were thus considered. At present, the study assumed the future agricultural water uses to be unchanged under climatic changes. In this connection, EPIC model is underway to use for estimating future agricultural water demand under climatic changes on a monthly basis. From

  6. Global-mean marine δ13C and its uncertainty in a glacial state estimate

    NASA Astrophysics Data System (ADS)

    Gebbie, Geoffrey; Peterson, Carlye D.; Lisiecki, Lorraine E.; Spero, Howard J.

    2015-10-01

    A paleo-data compilation with 492 δ13C and δ18O observations provides the opportunity to better sample the Last Glacial Maximum (LGM) and infer its global properties, such as the mean δ13C of dissolved inorganic carbon. Here, the paleo-compilation is used to reconstruct a steady-state water-mass distribution for the LGM, that in turn is used to map the data onto a 3D global grid. A global-mean marine δ13C value and a self-consistent uncertainty estimate are derived using the framework of state estimation (i.e., combining a numerical model and observations). The LGM global-mean δ13C is estimated to be 0.14‰ ± 0.20‰ at the two standard error level, giving a glacial-to-modern change of 0.32‰ ± 0.20‰. The magnitude of the error bar is attributed to the uncertain glacial ocean circulation and the lack of observational constraints in the Pacific, Indian, and Southern Oceans. To halve the error bar, roughly four times more observations are needed, although strategic sampling may reduce this number. If dynamical constraints can be used to better characterize the LGM circulation, the error bar can also be reduced to 0.05 to 0.1‰, emphasizing that knowledge of the circulation is vital to accurately map δ13C in three dimensions.

  7. An empirical model for global earthquake fatality estimation

    USGS Publications Warehouse

    Jaiswal, Kishor; Wald, David

    2010-01-01

    We analyzed mortality rates of earthquakes worldwide and developed a country/region-specific empirical model for earthquake fatality estimation within the U. S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) system. The earthquake fatality rate is defined as total killed divided by total population exposed at specific shaking intensity level. The total fatalities for a given earthquake are estimated by multiplying the number of people exposed at each shaking intensity level by the fatality rates for that level and then summing them at all relevant shaking intensities. The fatality rate is expressed in terms of a two-parameter lognormal cumulative distribution function of shaking intensity. The parameters are obtained for each country or a region by minimizing the residual error in hindcasting the total shaking-related deaths from earthquakes recorded between 1973 and 2007. A new global regionalization scheme is used to combine the fatality data across different countries with similar vulnerability traits. [DOI: 10.1193/1.3480331

  8. Fissile mass estimation by pulsed neutron source interrogation

    NASA Astrophysics Data System (ADS)

    Israelashvili, I.; Dubi, C.; Ettedgui, H.; Ocherashvili, A.; Pedersen, B.; Beck, A.; Roesgen, E.; Crochmore, J. M.; Ridnik, T.; Yaar, I.

    2015-06-01

    Passive methods for detecting correlated neutrons from spontaneous fissions (e.g. multiplicity and SVM) are widely used for fissile mass estimations. These methods can be used for fissile materials that emit a significant amount of fission neutrons (like plutonium). Active interrogation, in which fissions are induced in the tested material by an external continuous source or by a pulsed neutron source, has the potential advantages of fast measurement, alongside independence of the spontaneous fissions of the tested fissile material, thus enabling uranium measurement. Until recently, using the multiplicity method, for uranium mass estimation, was possible only for active interrogation made with continues neutron source. Pulsed active neutron interrogation measurements were analyzed with techniques, e.g. differential die away analysis (DDA), which ignore or implicitly include the multiplicity effect (self-induced fission chains). Recently, both, the multiplicity and the SVM techniques, were theoretically extended for analyzing active fissile mass measurements, made by a pulsed neutron source. In this study the SVM technique for pulsed neutron source is experimentally examined, for the first time. The measurements were conducted at the PUNITA facility of the Joint Research Centre in Ispra, Italy. First promising results, of mass estimation by the SVM technique using a pulsed neutron source, are presented.

  9. Global Estimates of PBL Depth from Space-Borne LIDAR

    NASA Technical Reports Server (NTRS)

    McGrath-Spangler, Erica lynn; Denning, S.; Molod, A.; Ott, L.

    2012-01-01

    The planetary boundary layer (PBL) is responsible for communicating the exchange of energy, moisture, momentum, pollutants, and aerosols between the surface and the free atmosphere and is therefore crucial to many studies of the atmosphere. Unfortunately, there have historically been few observations of this important layer due to the complexity involved in its measurement. However, with the advent of more advanced satellites, global measurements of the PBL are now becoming possible. The PBL is often characterized by a high concentration of aerosols within the layer and low level clouds capping it and these are observable from space. The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite was launched in 2006 with the intention of observing aerosols and clouds and was the first space-based LIDAR optimized for this purpose. CALIPSO observations are therefore well suited to observing the depth of the PBL. Since it was launched, CALIPSO has been making nearly continuous measurements enabling a global picture of PBL depth. We plan to present a global PBL depth product and how it evolves throughout the year. The product is able to identify deeper PBL depths in the summer hemisphere over land and deeper depths along the northern hemisphere oceanic storm tracks in winter associated with cold air traveling over warm water. Large seasonal cycles are also evident in the subtropical desert locations among other features. In addition, comparisons will be made between several estimates of PBL depth based on turbulent intensity, meteorology profiles, and aerosol profiles from the GEOS5 model.

  10. Global and regional emissions estimates for N2O

    NASA Astrophysics Data System (ADS)

    Saikawa, E.; Prinn, R. G.; Dlugokencky, E. J.; Ishijima, K.; Dutton, G. S.; Hall, B. D.; Langenfelds, R.; Tohjima, Y.; Machida, T.; Manizza, M.; Rigby, M. L.; Odoherty, S. J.; Patra, P. K.; Harth, C.; Weiss, R. F.; Krummel, P. B.; van der Schoot, M.; Fraser, P.; Steele, P.; Aoki, S.; Nakazawa, T.; Elkins, J. W.

    2013-12-01

    We present a comprehensive estimate of nitrous oxide (N2O) emissions using observations and models from 1995 to 2008. High-frequency records of tropospheric N2O are available from measurements at Cape Grim, Tasmania; Cape Matatula, American Samoa; Ragged Point, Barbados; Mace Head, Ireland; and at Trinidad Head, California using the Advanced Global Atmospheric Gases Experiment (AGAGE) instrumentation and calibrations. The Global Monitoring Division of the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) has also discrete air samples collected in flasks and in situ measurements from remote sites across the globe and analyzed them for a suite of species including N2O. In addition to these major networks, we include in situ and aircraft measurements from the National Institute for Environmental Studies (NIES) and flask measurements from the Tohoku University and Commonwealth Scientific and Industrial Research Organization (CSIRO) networks. All measurements show increasing atmospheric mole fractions of N2O, with a varying growth rate of 0.1-0.7%yr-1, resulting in a 7.4% increase in the background atmospheric mole fraction between 1979 and 2011. Using existing emission inventories as well as bottom-up process modeling results, we first create globally-gridded a priori N2O emissions over the 37 yr since 1975. We then use the three-dimensional chemical transport model, Model for Ozone and Related Chemical Tracers version 4 (MOZART v4), and a Bayesian inverse method to estimate global as well as regional annual emissions for five source sectors from 13 regions in the world. This is the first time that all of these measurements from multiple networks have been combined to determine emissions. Our inversion indicates that global and regional N2O emissions have an increasing trend between 1995 and 2008. Despite large uncertainties, a significant increase is seen from the Asian agricultural sector in the recent years, most likely due

  11. Global and regional emissions estimates for N2O

    NASA Astrophysics Data System (ADS)

    Saikawa, E.; Prinn, R. G.; Dlugokencky, E.; Ishijima, K.; Dutton, G. S.; Hall, B. D.; Langenfelds, R.; Tohjima, Y.; Machida, T.; Manizza, M.; Rigby, M.; O'Doherty, S.; Patra, P. K.; Harth, C. M.; Weiss, R. F.; Krummel, P. B.; van der Schoot, M.; Fraser, P. B.; Steele, L. P.; Aoki, S.; Nakazawa, T.; Elkins, J. W.

    2013-07-01

    We present a comprehensive estimate of nitrous oxide ( N2O) emissions using observations and models from 1995 to 2008. High-frequency records of tropospheric N2O are available from measurements at Cape Grim, Tasmania; Cape Matatula, American Samoa; Ragged Point, Barbados; Mace Head, Ireland; and at Trinidad Head, California using the Advanced Global Atmospheric Gases Experiment (AGAGE) instrumentation and calibrations. The Global Monitoring Division of the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) has also discrete air samples collected in flasks and in situ measurements from remote sites across the globe and analyzed them for a suite of species including N2O. In addition to these major networks, we include in situ and aircraft measurements from the National Institute for Environmental Studies (NIES) and flask measurements from the Tohoku University and Commonwealth Scientific and Industrial Research Organization (CSIRO) networks. All measurements show increasing atmospheric mole fractions of N2O, with a varying growth rate of 0.1-0.7 % yr-1, resulting in a 7.4% increase in the background atmospheric mole fraction between 1979 and 2011. Using existing emission inventories as well as bottom-up process modeling results, we first create globally-gridded a priori N2O emissions over the 37 yr since 1975. We then use the three-dimensional chemical transport model, Model for Ozone and Related Chemical Tracers version 4 (MOZART v4), and a Bayesian inverse method to estimate global as well as regional annual emissions for five source sectors from 13 regions in the world. This is the first time that all of these measurements from multiple networks have been combined to determine emissions. Our inversion indicates that global and regional N2O emissions have an increasing trend between 1995 and 2008. Despite large uncertainties, a significant increase is seen from the Asian agricultural sector in the recent years, most likely

  12. Global and regional emissions estimates for N2O

    NASA Astrophysics Data System (ADS)

    Saikawa, E.; Prinn, R. G.; Dlugokencky, E.; Ishijima, K.; Dutton, G. S.; Hall, B. D.; Langenfelds, R.; Tohjima, Y.; Machida, T.; Manizza, M.; Rigby, M.; O'Doherty, S.; Patra, P. K.; Harth, C. M.; Weiss, R. F.; Krummel, P. B.; van der Schoot, M.; Fraser, P. J.; Steele, L. P.; Aoki, S.; Nakazawa, T.; Elkins, J. W.

    2014-05-01

    We present a comprehensive estimate of nitrous oxide (N2O) emissions using observations and models from 1995 to 2008. High-frequency records of tropospheric N2O are available from measurements at Cape Grim, Tasmania; Cape Matatula, American Samoa; Ragged Point, Barbados; Mace Head, Ireland; and at Trinidad Head, California using the Advanced Global Atmospheric Gases Experiment (AGAGE) instrumentation and calibrations. The Global Monitoring Division of the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) has also collected discrete air samples in flasks and in situ measurements from remote sites across the globe and analyzed them for a suite of species including N2O. In addition to these major networks, we include in situ and aircraft measurements from the National Institute of Environmental Studies (NIES) and flask measurements from the Tohoku University and Commonwealth Scientific and Industrial Research Organization (CSIRO) networks. All measurements show increasing atmospheric mole fractions of N2O, with a varying growth rate of 0.1-0.7% per year, resulting in a 7.4% increase in the background atmospheric mole fraction between 1979 and 2011. Using existing emission inventories as well as bottom-up process modeling results, we first create globally gridded a priori N2O emissions over the 37 years since 1975. We then use the three-dimensional chemical transport model, Model for Ozone and Related Chemical Tracers version 4 (MOZART v4), and a Bayesian inverse method to estimate global as well as regional annual emissions for five source sectors from 13 regions in the world. This is the first time that all of these measurements from multiple networks have been combined to determine emissions. Our inversion indicates that global and regional N2O emissions have an increasing trend between 1995 and 2008. Despite large uncertainties, a significant increase is seen from the Asian agricultural sector in recent years, most likely

  13. Global coupled sea ice-ocean state estimation

    NASA Astrophysics Data System (ADS)

    Fenty, Ian; Menemenlis, Dimitris; Zhang, Hong

    2015-09-01

    We study the impact of synthesizing ocean and sea ice concentration data with a global, eddying coupled sea ice-ocean configuration of the Massachusetts Institute of Technology general circulation model with the goal of reproducing the 2004 three-dimensional time-evolving ice-ocean state. This work builds on the state estimation framework developed in the Estimating the Circulation and Climate of the Ocean consortium by seeking a reconstruction of the global sea ice-ocean system that is simultaneously consistent with (1) a suite of in situ and remotely-sensed ocean and ice data and (2) the physics encoded in the numerical model. This dual consistency is successfully achieved here by adjusting only the model's initial hydrographic state and its atmospheric boundary conditions such that misfits between the model and data are minimized in a least-squares sense. We show that synthesizing both ocean and sea ice concentration data is required for the model to adequately reproduce the observed details of the sea ice annual cycle in both hemispheres. Surprisingly, only modest adjustments to our first-guess atmospheric state and ocean initial conditions are necessary to achieve model-data consistency, suggesting that atmospheric reanalysis products remain a leading source of errors for sea ice-ocean model hindcasts and reanalyses. The synthesis of sea ice data is found to ameliorate misfits in the high latitude ocean, especially with respect to upper ocean stratification, temperature, and salinity. Constraining the model to sea ice concentration modestly reduces ICESat-derived Arctic ice thickness errors by improving the temporal and spatial evolution of seasonal ice. Further increases in the accuracy of global sea ice thickness in the model likely require the direct synthesis of sea ice thickness data.

  14. Sensitivity of Model Estimates of Contemporary Global and Regional Sea-Level Changes to Geothermal Flow

    NASA Astrophysics Data System (ADS)

    Piecuch, Christopher; Heimbach, Patrick; Ponte, Rui; Forget, Gael

    2015-04-01

    An ocean general circulation model in a global configuration, constrained to observations over the period 1993-2010 as part of the ECCO (Estimating the Circulation and Climate of the Ocean) project, has been used to to infer the influence of geothermal flow on estimates of contemporary sea level changes. Two distinct simulations are compared, which differ only with regard to whether they apply geothermal flow as a bottom boundary condition. Geothermal flow forcing increases the global mean sea level trend over 1993-2010 by 0.11 mm yr-1 in the perturbation simulation relative to the control simulation with no geothermal forcing, mostly due to increased net thermal expansion in the deep ocean (below 2000 m). The Southern Ocean is particularly sensitive to geothermal flow, with differences between regional sea level trends from the perturbation and control simulations up to ±1 mm yr-1 in some places. More generally, it is suggested that ocean heat transports redistribute the geothermal input along constant pressure surfaces and constant surfaces of temperature or salinity. This redistribution of heat results in stronger (weaker) steric height trend differences between the two solutions over deeper (shallower) areas, and effects anomalous redistribution of ocean mass from deeper to shallower areas in the perturbation solution relative to the control solution. Given the sparsity of heat flow measurements, ocean state estimation could (in principle) be a means to the end of constraining solid Earth heat flow estimates over the global ocean.

  15. Global estimates of evapotranspiration and gross primary production based on MODIS and global meteorology data

    USGS Publications Warehouse

    Yuan, W.; Liu, S.; Yu, G.; Bonnefond, J.-M.; Chen, J.; Davis, K.; Desai, A.R.; Goldstein, Allen H.; Gianelle, D.; Rossi, F.; Suyker, A.E.; Verma, S.B.

    2010-01-01

    The simulation of gross primary production (GPP) at various spatial and temporal scales remains a major challenge for quantifying the global carbon cycle. We developed a light use efficiency model, called EC-LUE, driven by only four variables: normalized difference vegetation index (NDVI), photosynthetically active radiation (PAR), air temperature, and the Bowen ratio of sensible to latent heat flux. The EC-LUE model may have the most potential to adequately address the spatial and temporal dynamics of GPP because its parameters (i.e., the potential light use efficiency and optimal plant growth temperature) are invariant across the various land cover types. However, the application of the previous EC-LUE model was hampered by poor prediction of Bowen ratio at the large spatial scale. In this study, we substituted the Bowen ratio with the ratio of evapotranspiration (ET) to net radiation, and revised the RS-PM (Remote Sensing-Penman Monteith) model for quantifying ET. Fifty-four eddy covariance towers, including various ecosystem types, were selected to calibrate and validate the revised RS-PM and EC-LUE models. The revised RS-PM model explained 82% and 68% of the observed variations of ET for all the calibration and validation sites, respectively. Using estimated ET as input, the EC-LUE model performed well in calibration and validation sites, explaining 75% and 61% of the observed GPP variation for calibration and validation sites respectively. Global patterns of ET and GPP at a spatial resolution of 0.5?? latitude by 0.6?? longitude during the years 2000-2003 were determined using the global MERRA dataset (Modern Era Retrospective-Analysis for Research and Applications) and MODIS (Moderate Resolution Imaging Spectroradiometer). The global estimates of ET and GPP agreed well with the other global models from the literature, with the highest ET and GPP over tropical forests and the lowest values in dry and high latitude areas. However, comparisons with observed GPP

  16. Mass center estimation of a drag-free satellite

    NASA Technical Reports Server (NTRS)

    Sanz Fernandez De Cordova, S.; Debra, D. B.

    1975-01-01

    The mass center location of a spinning drag-free satellite can be estimated because there is control required to accelerate the mass center along the axis of spin as long as there is some nutation in the spinning motion. Linear and nonlinear models are compared and observability discussed. Online estimation fails when nutation is damped so an offline mechanization is proposed. A new sensor has been designed to permit greater relative motion than was possible on the drag-free satellite flown in 1972 (JH-1). Experimental laboratory results using a spinning vehicle with the new sensor mounted 30 cm from a spherical air bearing support are presented which confirm earlier simulation results.

  17. An Iterated Global Mascon Solution with Focus on Land Ice Mass Evolution

    NASA Technical Reports Server (NTRS)

    Luthcke, S. B.; Sabaka, T.; Rowlands, D. D.; Lemoine, F. G.; Loomis, B. D.; Boy, J. P.

    2012-01-01

    Land ice mass evolution is determined from a new GRACE global mascon solution. The solution is estimated directly from the reduction of the inter-satellite K-band range rate observations taking into account the full noise covariance, and formally iterating the solution. The new solution increases signal recovery while reducing the GRACE KBRR observation residuals. The mascons are estimated with 10-day and 1-arc-degree equal area sampling, applying anisotropic constraints for enhanced temporal and spatial resolution of the recovered land ice signal. The details of the solution are presented including error and resolution analysis. An Ensemble Empirical Mode Decomposition (EEMD) adaptive filter is applied to the mascon solution time series to compute timing of balance seasons and annual mass balances. The details and causes of the spatial and temporal variability of the land ice regions studied are discussed.

  18. [Automatic Measurement of the Stellar Atmospheric Parameters Based Mass Estimation].

    PubMed

    Tu, Liang-ping; Wei, Hui-ming; Luo, A-li; Zhao, Yong-heng

    2015-11-01

    We have collected massive stellar spectral data in recent years, which leads to the research on the automatic measurement of stellar atmospheric physical parameters (effective temperature Teff, surface gravity log g and metallic abundance [Fe/ H]) become an important issue. To study the automatic measurement of these three parameters has important significance for some scientific problems, such as the evolution of the universe and so on. But the research of this problem is not very widely, some of the current methods are not able to estimate the values of the stellar atmospheric physical parameters completely and accurately. So in this paper, an automatic method to predict stellar atmospheric parameters based on mass estimation was presented, which can achieve the prediction of stellar effective temperature Teff, surface gravity log g and metallic abundance [Fe/H]. This method has small amount of computation and fast training speed. The main idea of this method is that firstly it need us to build some mass distributions, secondly the original spectral data was mapped into the mass space and then to predict the stellar parameter with the support vector regression (SVR) in the mass space. we choose the stellar spectral data from the United States SDSS-DR8 for the training and testing. We also compared the predicted results of this method with the SSPP and achieve higher accuracy. The predicted results are more stable and the experimental results show that the method is feasible and can predict the stellar atmospheric physical parameters effectively. PMID:26978937

  19. Estimation of left ventricular mass in conscious dogs

    NASA Technical Reports Server (NTRS)

    Coleman, Bernell; Cothran, Laval N.; Ison-Franklin, E. L.; Hawthorne, E. W.

    1986-01-01

    A method for the assessment of the development or the regression of left ventricular hypertrophy (LVH) in a conscious instrumented animal is described. First, the single-slice short-axis area-length method for estimating the left-ventricular mass (LVM) and volume (LVV) was validated in 24 formaldehyde-fixed canine hearts, and a regression equation was developed that could be used in the intact animal to correct the sonomicrometrically estimated LVM. The LVM-assessment method, which uses the combined techniques of echocardiography and sonomicrometry (in conjunction with the regression equation), was shown to provide reliable and reproducible day-to-day estimates of LVM and LVV, and to be sensitive enough to detect serial changes during the development of LVH.

  20. Spectral Approach to Optimal Estimation of the Global Average Temperature.

    NASA Astrophysics Data System (ADS)

    Shen, Samuel S. P.; North, Gerald R.; Kim, Kwang-Y.

    1994-12-01

    Making use of EOF analysis and statistical optimal averaging techniques, the problem of random sampling error in estimating the global average temperature by a network of surface stations has been investigated. The EOF representation makes it unnecessary to use simplified empirical models of the correlation structure of temperature anomalies. If an adjustable weight is assigned to each station according to the criterion of minimum mean-square error, a formula for this error can be derived that consists of a sum of contributions from successive EOF modes. The EOFs were calculated from both observed data and a noise-forced EBM for the problem of one-year and five-year averages. The mean square statistical sampling error depends on the spatial distribution of the stations, length of the averaging interval, and the choice of the weight for each station data stream. Examples used here include four symmetric configurations of 4 × 4, 6 × 4, 9 × 7, and 20 × 10 stations and the Angell-Korshover configuration. Comparisons with the 100-yr U.K. dataset show that correlations for the time series of the global temperature anomaly average between the full dataset and this study's sparse configurations are rather high. For example, the 63-station Angell-Korshover network with uniform weighting explains 92.7% of the total variance, whereas the same network with optimal weighting can lead to 97.8% explained total variance of the U.K. dataset.

  1. Spectral approach to optimal estimation of the global average temperature

    SciTech Connect

    Shen, S.S.P.; North, G.R.; Kim, K.Y.

    1994-12-01

    Making use of EOF analysis and statistical optimal averaging techniques, the problem of random sampling error in estimating the global average temperature by a network of surface stations has been investigated. The EOF representation makes it unnecessary to use simplified empirical models of the correlation structure of temperature anomalies. If an adjustable weight is assigned to each station according to the criterion of minimum mean-square error, a formula for this error can be derived that consists of a sum of contributions from successive EOF modes. The EOFs were calculated from both observed data a noise-forced EBM for the problem of one-year and five-year averages. The mean square statistical sampling error depends on the spatial distribution of the stations, length of the averaging interval, and the choice of the weight for each station data stream. Examples used here include four symmetric configurations of 4 X 4, 5 X 4, 9 X 7, and 20 X 10 stations and the Angell-Korshover configuration. Comparisons with the 100-yr U.K. dataset show that correlations for the time series of the global temperature anomaly average between the full dataset and this study`s sparse configurations are rather high. For example, the 63-station Angell-Korshover network with uniform weighting explains 92.7% of the total variance, whereas the same network with optimal weighting can lead to 97.8% explained total variance of the U.K. dataset. 27 refs., 5 figs., 4 tabs.

  2. TOPEX/POSEIDON tides estimated using a global inverse model

    NASA Technical Reports Server (NTRS)

    Egbert, Gary D.; Bennett, Andrew F.; Foreman, Michael G. G.

    1994-01-01

    Altimetric data from the TOPEX/POSEIDON mission will be used for studies of global ocean circulation and marine geophysics. However, it is first necessary to remove the ocean tides, which are aliased in the raw data. The tides are constrained by the two distinct types of information: the hydrodynamic equations which the tidal fields of elevations and velocities must satisfy, and direct observational data from tide gauges and satellite altimetry. Here we develop and apply a generalized inverse method, which allows us to combine rationally all of this information into global tidal fields best fitting both the data and the dynamics, in a least squares sense. The resulting inverse solution is a sum of the direct solution to the astronomically forced Laplace tidal equations and a linear combination of the representers for the data functionals. The representer functions (one for each datum) are determined by the dynamical equations, and by our prior estimates of the statistics or errors in these equations. Our major task is a direct numerical calculation of these representers. This task is computationally intensive, but well suited to massively parallel processing. By calculating the representers we reduce the full (infinite dimensional) problem to a relatively low-dimensional problem at the outset, allowing full control over the conditioning and hence the stability of the inverse solution. With the representers calculated we can easily update our model as additional TOPEX/POSEIDON data become available. As an initial illustration we invert harmonic constants from a set of 80 open-ocean tide gauges. We then present a practical scheme for direct inversion of TOPEX/POSEIDON crossover data. We apply this method to 38 cycles of geophysical data records (GDR) data, computing preliminary global estimates of the four principal tidal constituents, M(sub 2), S(sub 2), K(sub 1) and O(sub 1). The inverse solution yields tidal fields which are simultaneously smoother, and in better

  3. A global synthesis of survival estimates for microbats

    PubMed Central

    Lentini, Pia E.; Bird, Tomas J.; Griffiths, Stephen R.; Godinho, Lisa N.; Wintle, Brendan A.

    2015-01-01

    Accurate survival estimates are needed to construct robust population models, which are a powerful tool for understanding and predicting the fates of species under scenarios of environmental change. Microbats make up 17% of the global mammalian fauna, yet the processes that drive differences in demographics between species are poorly understood. We collected survival estimates for 44 microbat species from the literature and constructed a model to determine the effects of reproductive, feeding and demographic traits on survival. Our trait-based model indicated that bat species which produce more young per year exhibit lower apparent annual survival, as do males and juveniles compared with females and adults, respectively. Using 8 years of monitoring data for two Australian species, we demonstrate how knowledge about the effect of traits on survival can be incorporated into Bayesian survival analyses. This approach can be applied to any group and is not restricted to bats or even mammals. The incorporation of informative priors based on traits can allow for more timely construction of population models to support management decisions and actions. PMID:26246334

  4. Leishmaniasis Worldwide and Global Estimates of Its Incidence

    PubMed Central

    Vélez, Iván D.; Bern, Caryn; Herrero, Mercé; Desjeux, Philippe; Cano, Jorge; Jannin, Jean

    2012-01-01

    As part of a World Health Organization-led effort to update the empirical evidence base for the leishmaniases, national experts provided leishmaniasis case data for the last 5 years and information regarding treatment and control in their respective countries and a comprehensive literature review was conducted covering publications on leishmaniasis in 98 countries and three territories (see ‘Leishmaniasis Country Profiles Text S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31, S32, S33, S34, S35, S36, S37, S38, S39, S40, S41, S42, S43, S44, S45, S46, S47, S48, S49, S50, S51, S52, S53, S54, S55, S56, S57, S58, S59, S60, S61, S62, S63, S64, S65, S66, S67, S68, S69, S70, S71, S72, S73, S74, S75, S76, S77, S78, S79, S80, S81, S82, S83, S84, S85, S86, S87, S88, S89, S90, S91, S92, S93, S94, S95, S96, S97, S98, S99, S100, S101’). Additional information was collated during meetings conducted at WHO regional level between 2007 and 2011. Two questionnaires regarding epidemiology and drug access were completed by experts and national program managers. Visceral and cutaneous leishmaniasis incidence ranges were estimated by country and epidemiological region based on reported incidence, underreporting rates if available, and the judgment of national and international experts. Based on these estimates, approximately 0.2 to 0.4 cases and 0.7 to 1.2 million VL and CL cases, respectively, occur each year. More than 90% of global VL cases occur in six countries: India, Bangladesh, Sudan, South Sudan, Ethiopia and Brazil. Cutaneous leishmaniasis is more widely distributed, with about one-third of cases occurring in each of three epidemiological regions, the Americas, the Mediterranean basin, and western Asia from the Middle East to Central Asia. The ten countries with the highest estimated case counts, Afghanistan, Algeria, Colombia, Brazil, Iran, Syria, Ethiopia, North Sudan, Costa

  5. A global estimate of the Earth's magnetic crustal thickness

    NASA Astrophysics Data System (ADS)

    Vervelidou, Foteini; Thébault, Erwan

    2014-05-01

    The Earth's lithosphere is considered to be magnetic only down to the Curie isotherm. Therefore the Curie isotherm can, in principle, be estimated by analysis of magnetic data. Here, we propose such an analysis in the spectral domain by means of a newly introduced regional spatial power spectrum. This spectrum is based on the Revised Spherical Cap Harmonic Analysis (R-SCHA) formalism (Thébault et al., 2006). We briefly discuss its properties and its relationship with the Spherical Harmonic spatial power spectrum. This relationship allows us to adapt any theoretical expression of the lithospheric field power spectrum expressed in Spherical Harmonic degrees to the regional formulation. We compared previously published statistical expressions (Jackson, 1994 ; Voorhies et al., 2002) to the recent lithospheric field models derived from the CHAMP and airborne measurements and we finally developed a new statistical form for the power spectrum of the Earth's magnetic lithosphere that we think provides more consistent results. This expression depends on the mean magnetization, the mean crustal thickness and a power law value that describes the amount of spatial correlation of the sources. In this study, we make a combine use of the R-SCHA surface power spectrum and this statistical form. We conduct a series of regional spectral analyses for the entire Earth. For each region, we estimate the R-SCHA surface power spectrum of the NGDC-720 Spherical Harmonic model (Maus, 2010). We then fit each of these observational spectra to the statistical expression of the power spectrum of the Earth's lithosphere. By doing so, we estimate the large wavelengths of the magnetic crustal thickness on a global scale that are not accessible directly from the magnetic measurements due to the masking core field. We then discuss these results and compare them to the results we obtained by conducting a similar spectral analysis, but this time in the cartesian coordinates, by means of a published

  6. Center of Mass Estimation for a Spinning Spacecraft Using Doppler Shift of the GPS Carrier Frequency

    NASA Technical Reports Server (NTRS)

    Sedlak, Joseph E.

    2016-01-01

    A sequential filter is presented for estimating the center of mass (CM) of a spinning spacecraft using Doppler shift data from a set of onboard Global Positioning System (GPS) receivers. The advantage of the proposed method is that it is passive and can be run continuously in the background without using commanded thruster firings to excite spacecraft dynamical motion for observability. The NASA Magnetospheric Multiscale (MMS) mission is used as a test case for the CM estimator. The four MMS spacecraft carry star cameras for accurate attitude and spin rate estimation. The angle between the spacecraft nominal spin axis (for MMS this is the geometric body Z-axis) and the major principal axis of inertia is called the coning angle. The transverse components of the estimated rate provide a direct measure of the coning angle. The coning angle has been seen to shift slightly after every orbit and attitude maneuver. This change is attributed to a small asymmetry in the fuel distribution that changes with each burn. This paper shows a correlation between the apparent mass asymmetry deduced from the variations in the coning angle and the CM estimates made using the GPS Doppler data. The consistency between the changes in the coning angle and the CM provides validation of the proposed GPS Doppler method for estimation of the CM on spinning spacecraft.

  7. Mass Loss and Surface Displacement Estimates in Greenland from GRACE

    NASA Astrophysics Data System (ADS)

    Jensen, Tim; Forsberg, Rene

    2015-04-01

    The estimation of ice sheet mass changes from GRACE is basically an inverse problem, the solution is non-unique and several procedures for determining the mass distribution exists. We present Greenland mass loss results from two such procedures, namely a direct spherical harmonic inversion procedure possible through a thin layer assumption, and a generalized inverse masscon procedure. These results are updated to the end of 2014, including the unusual 2013 mass gain anomaly, and show a good agreement when taking into account leakage from the Canadian Icecaps. The GRACE mass changes are further compared to GPS uplift data on the bedrock along the edge of the ice sheet. The solid Earth deformation is assumed to consist of an elastic deformation of the crust and an anelastic deformation of the underlying mantle (GIA). The crustal deformation is due to current surface loading effects and therefore contains a strong seasonal component of variation, superimposed on a secular trend. The majority of the anelastic GIA deformation of the mantle is believed to be approximately constant. An accelerating secular trend and seasonal changes, as seen in Greenland, is therefore assumed to be due to elastic deformation from changes in surface mass loading from the ice sheet. The GRACE and GPS comparison is only valid by assuring that the signal content of the two observables are consistent. The GPS receivers are measuring movement at a single point on the bedrock surface, and therefore sensitive to a limited loading footprint, while the GRACE satellites on the other hand measures a filtered, attenuated gravitational field, at an altitude of approximately 500 km, making it sensitive to a much larger area. Despite this, the seasonal loading signal in the two observables show a reasonably good agreement.

  8. New Method of Estimating Binary's Mass Ratios by Using Superhumps

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Osaki, Yoji

    2013-12-01

    We propose a new dynamical method of estimating binary's mass ratios by using the period of superhumps in SU UMa-type dwarf novae during the growing stage (the stage A superhumps). This method is based on the working hypothesis that the period of superhumps in the growing stage is determined by the dynamical precession rate at the 3:1 resonance radius, and is suggested in our new interpretation of the superhump period evolution during a superoutburst (2013, PASJ, 65, 95). By comparing objects having known mass ratios, we show that our method can provide sufficiently accurate mass ratios comparable to those obtained by eclipse observations in quiescence. One of the advantages of this method is that it requires neither an eclipse nor any experimental calibration. It is particularly suitable for exploring the low mass-ratio end of the evolution of cataclysmic variables, where the secondary is not detectable by conventional methods. Our analysis suggests that previous determinations of the mass ratio by using superhump periods during a superoutburst were systematically underestimated for low mass-ratio systems, and we provided a new calibration. It reveals that most WZ Sge-type dwarf novae have either secondaries close to the border of the lower main-sequence or brown dwarfs, and most of the objects have not yet reached the evolutionary stage of period bouncers. Our results are not in contradiction with an assumption that an observed minimum period (˜77 min) of ordinary hydrogen-rich cataclysmic variables is indeed the minimum period. We highlight how important the early observation of stage A superhumps is, and propose an effective future strategy of observation.

  9. Utilizing Ion-Mobility Data to Estimate Molecular Masses

    NASA Technical Reports Server (NTRS)

    Duong, Tuan; Kanik, Isik

    2008-01-01

    A method is being developed for utilizing readings of an ion-mobility spectrometer (IMS) to estimate molecular masses of ions that have passed through the spectrometer. The method involves the use of (1) some feature-based descriptors of structures of molecules of interest and (2) reduced ion mobilities calculated from IMS readings as inputs to (3) a neural network. This development is part of a larger effort to enable the use of IMSs as relatively inexpensive, robust, lightweight instruments to identify, via molecular masses, individual compounds or groups of compounds (especially organic compounds) that may be present in specific environments or samples. Potential applications include detection of organic molecules as signs of life on remote planets, modeling and detection of biochemicals of interest in the pharmaceutical and agricultural industries, and detection of chemical and biological hazards in industrial, homeland-security, and industrial settings.

  10. Catastrophic Expenditure to Pay for Surgery: A Global Estimate

    PubMed Central

    Shrime, Mark G.; Dare, Anna J.; Alkire, Blake C.; O'Neill, Kathleen; Meara, John G.

    2015-01-01

    Purpose Approximately 150 million individuals face catastrophic expenditure each year from medical costs alone, and many more from the nonmedical costs of accessing care. The proportion of this expenditure arising from surgical conditions is unknown. Because World Bank has proposed eliminating medical impoverishment by 2030, the impact of surgical conditions on financial catastrophe must be quantified so that any financial risk protection mechanisms can appropriately incorporate surgery. Methods To determine the global incidence of catastrophic expenditure due to surgery, a stochastic model was built. The income distribution of each country, the probability of requiring surgery, and the medical and nonmedical costs faced for surgery were incorporated. Sensitivity analyses were run to test model robustness. Findings 3.7 billion people risk catastrophic expenditure if they need surgery. Every year, 33 million of them are driven to financial catastrophe from the costs of surgery alone, and 48 million from nonmedical costs, leading to 81 million cases worldwide. The burden of catastrophic expenditure is highest in low- and middle-income countries; within any country, it falls on the poor. Estimates are sensitive to the definition of catastrophic expenditure and the costs of care. The inequitable burden distribution is robust to model assumptions. Interpretation Half the global population is at risk of financial catastrophe from surgery. Annually, 81 million individuals, especially the poor, face catastrophic expenditure due to surgical conditions, of which less than half is attributable to medical costs. These findings highlight the need for financial risk protection for surgery in health system design. Funding Partial funding for Dr. Shrime from NIH/NCI R25CA92203. PMID:25926319

  11. Estimation of brassylic acid by gas chromatography-mass spectrometry

    SciTech Connect

    Mohammed J. Nasrullah, Erica N. Pfarr, Pooja Thapliyal, Nicholas S. Dusek, Kristofer L. Schiele, Christy Gallagher-Lein, and James A. Bahr

    2010-10-29

    The main focus of this work is to estimate Brassylic Acid (BA) using gas chromatography-mass spectrometry (GC-MS). BA is a product obtained from the oxidative cleavage of Erucic Acid (EA). BA has various applications for making nylons and high performance polymers. BA is a 13 carbon compound with two carboxylic acid functional groups at the terminal end. BA has a long hydrocarbon chain that makes the molecule less sensitive to some of the characterization techniques. Although BA can be characterized by NMR, both the starting material (EA) and products BA and nonanoic acid (NA) have peaks at similar {delta}, ppm values. Hence it becomes difficult for the quick estimation of BA during its synthesis.

  12. Estimated impact of global population growth on future wilderness extent

    NASA Astrophysics Data System (ADS)

    Dumont, E.

    2012-06-01

    Wilderness areas in the world are threatened by the environmental impacts of the growing global human population. This study estimates the impact of birth rate on the future surface area of biodiverse wilderness and on the proportion of this area without major extinctions. The following four drivers are considered: human population growth (1), agricultural efficiency (2), groundwater drawdown by irrigation (3), and non-agricultural space used by humans (buildings, gardens, roads, etc.) (4). This study indicates that the surface area of biodiverse unmanaged land will reduce with about 5.4% between 2012 and 2050. Further, it indicates that the biodiverse land without major extinctions will reduce with about 10.5%. These percentages are based on a commonly used population trajectory which assumes that birth rates across the globe will reduce in a similar way as has occurred in the past in many developed countries. Future birth rate is however very uncertain. Plausible future birth rates lower than the expected rates lead to much smaller reductions in surface area of biodiverse unmanaged land (0.7% as opposed to 5.4%), and a reduction in the biodiverse land without major extinctions of about 5.6% (as opposed to 10.5%). This indicates that birth rate is an important factor influencing the quality and quantity of wilderness remaining in the future.

  13. Global cost estimates of reducing carbon emissions through avoided deforestation

    PubMed Central

    Kindermann, Georg; Obersteiner, Michael; Sohngen, Brent; Sathaye, Jayant; Andrasko, Kenneth; Rametsteiner, Ewald; Schlamadinger, Bernhard; Wunder, Sven; Beach, Robert

    2008-01-01

    Tropical deforestation is estimated to cause about one-quarter of anthropogenic carbon emissions, loss of biodiversity, and other environmental services. United Nations Framework Convention for Climate Change talks are now considering mechanisms for avoiding deforestation (AD), but the economic potential of AD has yet to be addressed. We use three economic models of global land use and management to analyze the potential contribution of AD activities to reduced greenhouse gas emissions. AD activities are found to be a competitive, low-cost abatement option. A program providing a 10% reduction in deforestation from 2005 to 2030 could provide 0.3–0.6 Gt (1 Gt = 1 × 105 g) CO2·yr−1 in emission reductions and would require $0.4 billion to $1.7 billion·yr−1 for 30 years. A 50% reduction in deforestation from 2005 to 2030 could provide 1.5–2.7 Gt CO2·yr−1 in emission reductions and would require $17.2 billion to $28.0 billion·yr−1. Finally, some caveats to the analysis that could increase costs of AD programs are described. PMID:18650377

  14. Global estimation of potential unreported plutonium in thermal research reactors

    SciTech Connect

    Dreicer, J.S.; Rutherford, D.A.

    1996-09-01

    As of November, 1993, 303 research reactors (research, test, training, prototype, and electricity producing) were operational worldwide; 155 of these were in non-nuclear weapon states. Of these 155 research reactors, 80 are thermal reactors that have a power rating of 1 MW(th) or greater and could be utilized to produce plutonium. A previously published study on the unreported plutonium production of six research reactors indicates that a minimum reactor power of 40 MW (th) is required to make a significant quantity (SQ), 8 kg, of fissile plutonium per year by unreported irradiations. As part of the Global Nuclear Material Control Model effort, we determined an upper bound on the maximum possible quantity of plutonium that could be produced by the 80 thermal research reactors in the non-nuclear weapon states (NNWS). We estimate that in one year a maximum of roughly one quarter of a metric ton (250 kg) of plutonium could be produced in these 80 NNWS thermal research reactors based on their reported power output. We have calculated the quantity of plutonium and the number of years that would be required to produce an SQ of plutonium in the 80 thermal research reactors and aggregated by NNWS. A safeguards approach for multiple thermal research reactors that can produce less than 1 SQ per year should be conducted in association with further developing a safeguards and design information reverification approach for states that have multiple research reactors.

  15. Externally driven global Alfvén eigenmodes applied for effective mass number measurement on TCABR

    SciTech Connect

    Puglia, P. G. P. P.; Elfimov, A. G.; Ruchko, L. F.; Galvão, R. M. O.; Guimarães-Filho, Z.; Ronchi, G.

    2014-12-15

    The excitation and detection of Global Alfvén Eigenmodes on TCABR for diagnostic purposes are presented. The modes can be excited with one or two in-vessel antennae, with up to 15 A of current in each, in the frequency range from 2 to 4 MHz. This scheme allows the estimation of the effective mass number at the plasma center, which value is affected by impurity concentration in the core. An amplifier based on MOSFETs is used to excite the waves driven by low power, in order to not change the basic plasma parameters. The variation of the GAE with density is verified and the location of the mode resonance at the plasma center is confirmed by the sawtooth beating, so that the correspondingly beating phase inversion improves the precision on the resonant condition determination. The toroidal parity of the modes N = 1,2 is determined by use of two opposite located antennae with different phase of the RF current. Knowledge of toroidal mode number is important as it identifies GAE location and defines the estimated effective mass value. The estimated value for A{sub eff} is ∼1.4–1.5, corresponding to 5–7% of carbon impurity concentration. The measured value of A{sub eff} is used to estimate Z{sub eff}, which is compared to older TCA experiments and the value obtained by the Spitzer conductivity.

  16. Target prices for mass production of tyrosine kinase inhibitors for global cancer treatment

    PubMed Central

    Hill, Andrew; Gotham, Dzintars; Fortunak, Joseph; Meldrum, Jonathan; Erbacher, Isabelle; Martin, Manuel; Shoman, Haitham; Levi, Jacob; Powderly, William G; Bower, Mark

    2016-01-01

    Objective To calculate sustainable generic prices for 4 tyrosine kinase inhibitors (TKIs). Background TKIs have proven survival benefits in the treatment of several cancers, including chronic myeloid leukaemia, breast, liver, renal and lung cancer. However, current high prices are a barrier to treatment. Mass production of low-cost generic antiretrovirals has led to over 13 million people being on HIV/AIDS treatment worldwide. This analysis estimates target prices for generic TKIs, assuming similar methods of mass production. Methods Four TKIs with patent expiry dates in the next 5 years were selected for analysis: imatinib, erlotinib, lapatinib and sorafenib. Chemistry, dosing, published data on per-kilogram pricing for commercial transactions of active pharmaceutical ingredient (API), and quotes from manufacturers were used to estimate costs of production. Analysis included costs of excipients, formulation, packaging, shipping and a 50% profit margin. Target prices were compared with current prices. Global numbers of patients eligible for treatment with each TKI were estimated. Results API costs per kg were $347–$746 for imatinib, $2470 for erlotinib, $4671 for lapatinib, and $3000 for sorafenib. Basing on annual dose requirements, costs of formulation/packaging and a 50% profit margin, target generic prices per person-year were $128–$216 for imatinib, $240 for erlotinib, $1450 for sorafenib, and $4020 for lapatinib. Over 1 million people would be newly eligible to start treatment with these TKIs annually. Conclusions Mass generic production of several TKIs could achieve treatment prices in the range of $128–$4020 per person-year, versus current US prices of $75161–$139 138. Generic TKIs could allow significant savings and scaling-up of treatment globally, for over 1 million eligible patients. PMID:26817636

  17. Water mass age and aging driving chromophoric dissolved organic matter in the dark global ocean

    NASA Astrophysics Data System (ADS)

    Catalá, T. S.; Reche, I.; Álvarez, M.; Khatiwala, S.; Guallart, E. F.; Benítez-Barrios, V. M.; Fuentes-Lema, A.; Romera-Castillo, C.; Nieto-Cid, M.; Pelejero, C.; Fraile-Nuez, E.; Ortega-Retuerta, E.; Marrasé, C.; Álvarez-Salgado, X. A.

    2015-07-01

    The omnipresence of chromophoric dissolved organic matter (CDOM) in the open ocean enables its use as a tracer for biochemical processes throughout the global overturning circulation. We made an inventory of CDOM optical properties, ideal water age (τ), and apparent oxygen utilization (AOU) along the Atlantic, Indian, and Pacific Ocean waters sampled during the Malaspina 2010 expedition. A water mass analysis was applied to obtain intrinsic, hereinafter archetypal, values of τ, AOU, oxygen utilization rate (OUR), and CDOM absorption coefficients, spectral slopes and quantum yield for each one of the 22 water types intercepted during this circumnavigation. Archetypal values of AOU and OUR have been used to trace the differential influence of water mass aging and aging rates, respectively, on CDOM variables. Whereas the absorption coefficient at 325 nm (a325) and the fluorescence quantum yield at 340 nm (Φ340) increased, the spectral slope over the wavelength range 275-295 nm (S275-295) and the ratio of spectral slopes over the ranges 275-295 nm and 350-400 nm (SR) decreased significantly with water mass aging (AOU). Combination of the slope of the linear regression between archetypal AOU and a325 with the estimated global OUR allowed us to obtain a CDOM turnover time of 634 ± 120 years, which exceeds the flushing time of the dark ocean (>200 m) by 46%. This positive relationship supports the assumption of in situ production and accumulation of CDOM as a by-product of microbial metabolism as water masses turn older. Furthermore, our data evidence that global-scale CDOM quantity (a325) is more dependent on aging (AOU), whereas CDOM quality (S275-295, SR, Φ340) is more dependent on aging rate (OUR).

  18. On the uncertainties of stellar mass estimates via colour measurements

    NASA Astrophysics Data System (ADS)

    Roediger, Joel C.; Courteau, Stéphane

    2015-09-01

    Mass-to-light versus colour relations (MLCRs), derived from stellar population synthesis models, are widely used to estimate galaxy stellar masses (M*), yet a detailed investigation of their inherent biases and limitations is still lacking. We quantify several potential sources of uncertainty, using optical and near-infrared (NIR) photometry for a representative sample of nearby galaxies from the Virgo cluster. Our method for combining multiband photometry with MLCRs yields robust stellar masses, while errors in M* decrease as more bands are simultaneously considered. The prior assumptions in one's stellar population modelling dominate the error budget, creating a colour-dependent bias of up to 0.6 dex if NIR fluxes are used (0.3 dex otherwise). This matches the systematic errors associated with the method of spectral energy distribution (SED) fitting, indicating that MLCRs do not suffer from much additional bias. Moreover, MLCRs and SED fitting yield similar degrees of random error (˜0.1-0.14 dex) when applied to mock galaxies and, on average, equivalent masses for real galaxies with M* ˜ 108-11 M⊙. The use of integrated photometry introduces additional uncertainty in M* measurements, at the level of 0.05-0.07 dex. We argue that using MLCRs, instead of time-consuming SED fits, is justified in cases with complex model parameter spaces (involving, for instance, multiparameter star formation histories) and/or for large data sets. Spatially resolved methods for measuring M* should be applied for small sample sizes and/or when accuracies less than 0.1 dex are required. An appendix provides our MLCR transformations for 10 colour permutations of the grizH filter set.

  19. Galaxy cluster mass estimation from stacked spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Farahi, Arya; Evrard, August E.; Rozo, Eduardo; Rykoff, Eli S.; Wechsler, Risa H.

    2016-08-01

    We use simulated galaxy surveys to study: (i) how galaxy membership in redMaPPer clusters maps to the underlying halo population, and (ii) the accuracy of a mean dynamical cluster mass, Mσ(λ), derived from stacked pairwise spectroscopy of clusters with richness λ. Using ˜130 000 galaxy pairs patterned after the Sloan Digital Sky Survey (SDSS) redMaPPer cluster sample study of Rozo et al., we show that the pairwise velocity probability density function of central-satellite pairs with mi < 19 in the simulation matches the form seen in Rozo et al. Through joint membership matching, we deconstruct the main Gaussian velocity component into its halo contributions, finding that the top-ranked halo contributes ˜60 per cent of the stacked signal. The halo mass scale inferred by applying the virial scaling of Evrard et al. to the velocity normalization matches, to within a few per cent, the log-mean halo mass derived through galaxy membership matching. We apply this approach, along with miscentring and galaxy velocity bias corrections, to estimate the log-mean matched halo mass at z = 0.2 of SDSS redMaPPer clusters. Employing the velocity bias constraints of Guo et al., we find = ln (M30) + αm ln (λ/30) with M30 = 1.56 ± 0.35 × 1014 M⊙ and αm = 1.31 ± 0.06stat ± 0.13sys. Systematic uncertainty in the velocity bias of satellite galaxies overwhelmingly dominates the error budget.

  20. Moving towards a new paradigm for global flood risk estimation

    NASA Astrophysics Data System (ADS)

    Troy, Tara J.; Devineni, Naresh; Lima, Carlos; Lall, Upmanu

    2013-04-01

    model is implemented at a finer resolution (<=1km) in order to more accurately model streamflow under flood conditions and estimate inundation. This approach allows for efficient computational simulation of the hydrology when not under potential for flooding with high-resolution flood wave modeling when there is flooding potential. We demonstrate the results of this flood risk estimation system for the Ohio River basin in the United States, a large river basin that is historically prone to flooding, with the intention of using it to do global flood risk assessment.

  1. Estimation of Particulate Mass and Manganese Exposure Levels among Welders

    PubMed Central

    Hobson, Angela; Seixas, Noah; Sterling, David; Racette, Brad A.

    2011-01-01

    Background: Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. Methods: Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. Results: A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. Conclusions: This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures

  2. Hardware architecture design of a fast global motion estimation method

    NASA Astrophysics Data System (ADS)

    Liang, Chaobing; Sang, Hongshi; Shen, Xubang

    2015-12-01

    VLSI implementation of gradient-based global motion estimation (GME) faces two main challenges: irregular data access and high off-chip memory bandwidth requirement. We previously proposed a fast GME method that reduces computational complexity by choosing certain number of small patches containing corners and using them in a gradient-based framework. A hardware architecture is designed to implement this method and further reduce off-chip memory bandwidth requirement. On-chip memories are used to store coordinates of the corners and template patches, while the Gaussian pyramids of both the template and reference frame are stored in off-chip SDRAMs. By performing geometric transform only on the coordinates of the center pixel of a 3-by-3 patch in the template image, a 5-by-5 area containing the warped 3-by-3 patch in the reference image is extracted from the SDRAMs by burst read. Patched-based and burst mode data access helps to keep the off-chip memory bandwidth requirement at the minimum. Although patch size varies at different pyramid level, all patches are processed in term of 3x3 patches, so the utilization of the patch-processing circuit reaches 100%. FPGA implementation results show that the design utilizes 24,080 bits on-chip memory and for a sequence with resolution of 352x288 and frequency of 60Hz, the off-chip bandwidth requirement is only 3.96Mbyte/s, compared with 243.84Mbyte/s of the original gradient-based GME method. This design can be used in applications like video codec, video stabilization, and super-resolution, where real-time GME is a necessity and minimum memory bandwidth requirement is appreciated.

  3. Sequential estimation of surface water mass changes from daily satellite gravimetry data

    NASA Astrophysics Data System (ADS)

    Ramillien, G. L.; Frappart, F.; Gratton, S.; Vasseur, X.

    2015-03-01

    We propose a recursive Kalman filtering approach to map regional spatio-temporal variations of terrestrial water mass over large continental areas, such as South America. Instead of correcting hydrology model outputs by the GRACE observations using a Kalman filter estimation strategy, regional 2-by-2 degree water mass solutions are constructed by integration of daily potential differences deduced from GRACE K-band range rate (KBRR) measurements. Recovery of regional water mass anomaly averages obtained by accumulation of information of daily noise-free simulated GRACE data shows that convergence is relatively fast and yields accurate solutions. In the case of cumulating real GRACE KBRR data contaminated by observational noise, the sequential method of step-by-step integration provides estimates of water mass variation for the period 2004-2011 by considering a set of suitable a priori error uncertainty parameters to stabilize the inversion. Spatial and temporal averages of the Kalman filter solutions over river basin surfaces are consistent with the ones computed using global monthly/10-day GRACE solutions from official providers CSR, GFZ and JPL. They are also highly correlated to in situ records of river discharges (70-95 %), especially for the Obidos station where the total outflow of the Amazon River is measured. The sparse daily coverage of the GRACE satellite tracks limits the time resolution of the regional Kalman filter solutions, and thus the detection of short-term hydrological events.

  4. Using nonlinear programming to correct leakage and estimate mass change from GRACE observation and its application to Antarctica

    NASA Astrophysics Data System (ADS)

    Tang, Jingshi; Cheng, Haowen; Liu, Lin

    2012-11-01

    The Gravity Recovery And Climate Experiment (GRACE) mission has been providing high quality observations since its launch in 2002. Over the years, fruitful achievements have been obtained and the temporal gravity field has revealed the ongoing geophysical, hydrological and other processes. These discoveries help the scientists better understand various aspects of the Earth. However, errors exist in high degree and order spherical harmonics, which need to be processed before use. Filtering is one of the most commonly used techniques to smooth errors, yet it attenuates signals and also causes leakage of gravity signal into surrounding areas. This paper reports a new method to estimate the true mass change on the grid (expressed in equivalent water height or surface density). The mass change over the grid can be integrated to estimate regional or global mass change. This method assumes the GRACE-observed apparent mass change is only caused by the mass change on land. By comparing the computed and observed apparent mass change, the true mass change can be iteratively adjusted and estimated. The problem is solved with nonlinear programming (NLP) and yields solutions which are in good agreement with other GRACE-based estimates.

  5. A Revised Estimate of 20th Century Global Mean Sea Level

    NASA Astrophysics Data System (ADS)

    Hay, C.; Morrow, E.; Kopp, R. E., III; Mitrovica, J. X.

    2014-12-01

    One of the primary goals of paleo-sea level research is to assess the stability of ice sheets and glaciers in warming climates. In this context, the 20th century may be thought of as the most recent, recorded, and studied of all past episodes of warming. Over the past decade, a consensus has emerged in the literature that 20th century global mean sea level (GMSL), inferred from tide gauge records, rose at a mean rate of 1.6-1.9 mm/yr. This sea-level rise can be attributed to multiple sources, including thermal expansion of the oceans, ice sheet and glacier mass flux, and anthropogenic changes in land water storage. The Fifth Assessment Report of the IPCC summarized the estimated contributions of these sources over 1901-1990 and computed a total rate, using a bottom-up approach, of ~1.0 mm/yr, which falls significantly short of the rate inferred from tide gauge records. Using two independent probabilistic approaches that utilize models of glacial isostatic adjustment, ocean dynamics, and the sea-level fingerprints of rapid land-ice melt to analyze tide gauge records (Kalman smoothing and Gaussian process regression), we are able to close the 20th century sea-level budget and resolve the above enigma. Our revised estimate for the rate of GMSL rise during 1901-1990 is 1.1-1.3 mm/yr (90% credible interval). This value, which is ~20-30% less than previous estimates, suggests that the change in the GMSL rate from the 20th century to the last two decades (2.7 ± 0.4 mm/yr, consistent with past estimates) was greater than previous estimates. Moreover, since some forward projections of GMSL change into the next century are based in part on past estimates of GMSL change, our revised rate may impact projections of GMSL rise for the 21st century and beyond.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  7. Mass Influx of Cosmic Dust Estimated From Vertical Transport of Meteoric Metals

    NASA Astrophysics Data System (ADS)

    Liu, Alan Z.; Guo, Yafang; Gardner, Chester S.

    2016-04-01

    The mesospheric metal layers are formed by the vaporization of high-speed cosmic dust particles in the lower thermosphere and upper mesosphere. The vaporized atoms and ions are transported downward by waves and turbulence to chemical sinks below 85 km, where they form stable compounds. These compounds condense onto meteoric smoke particles and are then transported to the winter pole where they eventually settle onto the surface. The downward fluxes of the metal atoms are directly related to their meteoric influxes and chemical loss rates. In this paper we use Doppler lidar measurements of Na and Fe fluxes made by the University of Illinois and University of Colorado groups, and a chemical ablation model (CABMOD) developed at the University of Leeds, to constrain the velocity/mass distribution of the meteoroids entering the atmosphere and to derive an improved estimate for the global influx of cosmic dust. We find that the particles responsible for injecting a large fraction of the ablated material into the Earth's upper atmosphere, enter at relatively slow speeds and originate primarily from the Jupiter Family of Comets. The global mean Na influx is 21,500±1,100 atoms/cm2/s, which equals 372±18 kg/d for the global input of Na vapor and 186±24 t/d for the global influx of cosmic dust. The global mean Fe influx is 131,000±36,000 atoms/cm2/s, which equals 5.5±1.5 t/d for the global input of Na vapor.

  8. Estimated global nitrogen deposition using NO2 column density

    USGS Publications Warehouse

    Lu, Xuehe; Jiang, Hong; Zhang, Xiuying; Liu, Jinxun; Zhang, Zhen; Jin, Jiaxin; Wang, Ying; Xu, Jianhui; Cheng, Miaomiao

    2013-01-01

    Global nitrogen deposition has increased over the past 100 years. Monitoring and simulation studies of nitrogen deposition have evaluated nitrogen deposition at both the global and regional scale. With the development of remote-sensing instruments, tropospheric NO2 column density retrieved from Global Ozone Monitoring Experiment (GOME) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) sensors now provides us with a new opportunity to understand changes in reactive nitrogen in the atmosphere. The concentration of NO2 in the atmosphere has a significant effect on atmospheric nitrogen deposition. According to the general nitrogen deposition calculation method, we use the principal component regression method to evaluate global nitrogen deposition based on global NO2 column density and meteorological data. From the accuracy of the simulation, about 70% of the land area of the Earth passed a significance test of regression. In addition, NO2 column density has a significant influence on regression results over 44% of global land. The simulated results show that global average nitrogen deposition was 0.34 g m−2 yr−1 from 1996 to 2009 and is increasing at about 1% per year. Our simulated results show that China, Europe, and the USA are the three hotspots of nitrogen deposition according to previous research findings. In this study, Southern Asia was found to be another hotspot of nitrogen deposition (about 1.58 g m−2 yr−1 and maintaining a high growth rate). As nitrogen deposition increases, the number of regions threatened by high nitrogen deposits is also increasing. With N emissions continuing to increase in the future, areas whose ecosystem is affected by high level nitrogen deposition will increase.

  9. ESTIMATE OF GLOBAL METHANE EMISSIONS FROM COAL MINES

    EPA Science Inventory

    Country-specific emissions of methane (CH4) from underground coal mines, surface coal mines, and coal crushing and transport operations are estimated for 1989. Emissions for individual countries are estimated by using two sets of regression equations (R2 values range from 0.56 to...

  10. Global distribution of soil organic carbon - Part 1: Masses and frequency distributions of SOC stocks for the tropics, permafrost regions, wetlands, and the world

    NASA Astrophysics Data System (ADS)

    Köchy, M.; Hiederer, R.; Freibauer, A.

    2015-04-01

    The global soil organic carbon (SOC) mass is relevant for the carbon cycle budget and thus atmospheric carbon concentrations. We review current estimates of SOC stocks and mass (stock × area) in wetlands, permafrost and tropical regions and the world in the upper 1 m of soil. The Harmonized World Soil Database (HWSD) v.1.2 provides one of the most recent and coherent global data sets of SOC, giving a total mass of 2476 Pg when using the original values for bulk density. Adjusting the HWSD's bulk density (BD) of soil high in organic carbon results in a mass of 1230 Pg, and additionally setting the BD of Histosols to 0.1 g cm-3 (typical of peat soils), results in a mass of 1062 Pg. The uncertainty in BD of Histosols alone introduces a range of -56 to +180 Pg C into the estimate of global SOC mass in the top 1 m, larger than estimates of global soil respiration. We report the spatial distribution of SOC stocks per 0.5 arcminutes; the areal masses of SOC; and the quantiles of SOC stocks by continents, wetland types, and permafrost types. Depending on the definition of "wetland", wetland soils contain between 82 and 158 Pg SOC. With more detailed estimates for permafrost from the Northern Circumpolar Soil Carbon Database (496 Pg SOC) and tropical peatland carbon incorporated, global soils contain 1325 Pg SOC in the upper 1 m, including 421 Pg in tropical soils, whereof 40 Pg occurs in tropical wetlands. Global SOC amounts to just under 3000 Pg when estimates for deeper soil layers are included. Variability in estimates is due to variation in definitions of soil units, differences in soil property databases, scarcity of information about soil carbon at depths > 1 m in peatlands, and variation in definitions of "peatland".

  11. 3D viscosity maps for Greenland and effect on GRACE mass balance estimates

    NASA Astrophysics Data System (ADS)

    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.

  12. Estimates of Ice Sheet Mass Balance from Satellite Altimetry: Past and Future

    NASA Technical Reports Server (NTRS)

    Zwally, H. Jay; Zukor, Dorothy J. (Technical Monitor)

    2001-01-01

    A major uncertainty in predicting sea level rise is the sensitivity of ice sheet mass balance to climate change, as well as the uncertainty in present mass balance. Since the annual water exchange is about 8 mm of global sea level equivalent, the 20% uncertainty in current mass balance corresponds to 1.6 mm/yr in sea level change. Furthermore, estimates of the sensitivity of the mass balance to temperature change range from perhaps as much as - 10% to + 10% per K. A principal purpose of obtaining ice sheet elevation changes from satellite altimetry has been estimation of the current ice sheet mass balance. Limited information on ice sheet elevation change and their implications about mass balance have been reported by several investigators from radar altimetry (Seasat, Geosat, ERS-1&2). Analysis of ERS-1&2 data over Greenland for 7 years from 1992 to 1999 shows mixed patterns of ice elevation increases and decreases that are significant in terms of regional-scale mass balances. Observed seasonal and interannual variations in ice surface elevation are larger than previously expected because of seasonal and interannUal variations in precipitation, melting, and firn compaction. In the accumulation zone, the variations in firn compaction are modeled as a function of temperature leaving variations in precipitation and the mass balance trend. Significant interannual variations in elevation in some locations, in particular the difference in trends from 1992 to 1995 compared to 1995 to 1999, can be explained by changes in precipitation over Greenland. Over the 7 years, trends in elevation are mostly positive at higher elevations and negative at lower elevations. In addition, trends for the winter seasons (from a trend analysis through the average winter elevations) are more positive than the corresponding trends for the summer. At lower elevations, the 7-year trends in some locations are strongly negative for summer and near zero or slightly positive for winter. These

  13. Secondary metabolomics: natural products mass spectrometry goes global.

    PubMed

    Kersten, Roland D; Dorrestein, Pieter C

    2009-08-21

    A global LC-MS metabolite analysis of wild-type Pseudomonas auerigunosa and mutants targeting the natural product pyochelin revealed the production of previously unknown metabolites, the 2-alkyl-4,5-dihydrothiazole-4-carboxylates. PMID:19817465

  14. Zero-Point Calibration for AGN Black-Hole Mass Estimates

    NASA Technical Reports Server (NTRS)

    Peterson, B. M.; Onken, C. A.

    2004-01-01

    We discuss the measurement and associated uncertainties of AGN reverberation-based black-hole masses, since these provide the zero-point calibration for scaling relationships that allow black-hole mass estimates for quasars. We find that reverberation-based mass estimates appear to be accurate to within a factor of about 3.

  15. Global flood hazard mapping using statistical peak flow estimates

    NASA Astrophysics Data System (ADS)

    Herold, C.; Mouton, F.

    2011-01-01

    Our aim is to produce a world map of flooded areas for a 100 year return period, using a method based on large rivers peak flow estimates derived from mean monthly discharge time-series. Therefore, the map is supposed to represent flooding that affects large river floodplains, but not events triggered by specific conditions like coastal or flash flooding for instance. We first generate for each basin a set of hydromorphometric, land cover and climatic variables. In case of an available discharge record station at the basin outlet, we base the hundred year peak flow estimate on the corresponding time-series. Peak flow magnitude for basin outlets without gauging stations is estimated by statistical means, performing several regressions on the basin variables. These peak flow estimates enable the computation of corresponding flooded areas using hydrologic GIS processing on digital elevation model.

  16. The initial mass function and global rates of mass, momentum, and energy input to the interstellar medium via stellar winds

    NASA Technical Reports Server (NTRS)

    Van Buren, D.

    1985-01-01

    Published observational data are compiled and analyzed, using theoretical stellar-evolution models to determine the global rates of mass, momentum, and energy injected into the interstellar medium (ISM) by stellar winds. Expressions derived include psi = 0.00054 x (M to the -1.03) stars formed/sq kpc yr log M (where M is the initial mass function in solar mass units) and mass-loss = (2 x 10 to the -13th) x (L to the 1.25) solar mass/yr (with L in solar luminosity units). It is found that the wind/supernova injection of energy into the ISM and the mass loss from stars of 5 solar mass or more are approximately balanced by the dissipation of energy by cloud-cloud collisions and the formation of stars, respectively.

  17. Global parameter estimation methods for stochastic biochemical systems

    PubMed Central

    2010-01-01

    Background The importance of stochasticity in cellular processes having low number of molecules has resulted in the development of stochastic models such as chemical master equation. As in other modelling frameworks, the accompanying rate constants are important for the end-applications like analyzing system properties (e.g. robustness) or predicting the effects of genetic perturbations. Prior knowledge of kinetic constants is usually limited and the model identification routine typically includes parameter estimation from experimental data. Although the subject of parameter estimation is well-established for deterministic models, it is not yet routine for the chemical master equation. In addition, recent advances in measurement technology have made the quantification of genetic substrates possible to single molecular levels. Thus, the purpose of this work is to develop practical and effective methods for estimating kinetic model parameters in the chemical master equation and other stochastic models from single cell and cell population experimental data. Results Three parameter estimation methods are proposed based on the maximum likelihood and density function distance, including probability and cumulative density functions. Since stochastic models such as chemical master equations are typically solved using a Monte Carlo approach in which only a finite number of Monte Carlo realizations are computationally practical, specific considerations are given to account for the effect of finite sampling in the histogram binning of the state density functions. Applications to three practical case studies showed that while maximum likelihood method can effectively handle low replicate measurements, the density function distance methods, particularly the cumulative density function distance estimation, are more robust in estimating the parameters with consistently higher accuracy, even for systems showing multimodality. Conclusions The parameter estimation methodologies

  18. Estimating Black Hole Masses in Hundreds of Quasars

    NASA Astrophysics Data System (ADS)

    Hernitschek, Nina; Rix, Hans-Walter; Bovy, Jo; Morganson, Eric

    2015-03-01

    We explore the practical feasibility of active galactic nucleus (AGN) broadband reverberation mapping and present first results. We lay out and apply a rigorous approach for the stochastic reverberation mapping of unevenly sampled multi-broadband flux measurements, assuming that the broad-line region (BLR) line flux is contributing up to 15% in some bands, and is directly constrained by one spectroscopical epoch. The approach describes variations of the observed flux as the continuum, modeled as a stochastic Gaussian process, and emission line contribution, modeled as a scaled, smoothed, and delayed version of the continuum. This approach can be used not only to interpolate in time between measurements, but also to determine confidence limits on continuum—line emission delays. This approach is applied to Sloan Digital Sky Survey observations in Stripe 82 (S82), providing flux measurements that are precise to 2% at ~60 epochs over ~10 yr. The strong annual variations in the epoch sampling prove a serious limitation in practice. In addition, suitable redshift ranges must be identified where strong, broad emission lines contribute to one filter, but not to another. By generating and evaluating problem-specific mock data, we verify that S82-like data can constrain τdelay for a simple transfer function model. In application to real data, we estimate τdelay for 323 AGNs with 0.225 < z < 0.846, combining information for different objects through the ensemble-scaling relationships for BLR size and black hole mass. Our analysis tentatively indicates a 1.7 times larger BLR size of Hα and Mg II compared to Kaspi et al. and Vestergaard, but the seasonal data sampling casts doubt on the robustness of the inference.

  19. Organic Mass to Organic Carbon ratio in Atmospheric Aerosols: Observations and Global Simulations

    NASA Astrophysics Data System (ADS)

    Tsigaridis, K.; Kanakidou, M.; Daskalakis, N.

    2012-12-01

    Organic compounds play an important role in atmospheric chemistry and affect Earth's climate through their impact on oxidants and aerosol formation (e.g. O3 and organic aerosols (OA)). Due to the complexity of the mixture of organics in the atmosphere, the organic-mass-to-organic-carbon ratio (OM/OC) is often used to characterize the organic component in atmospheric aerosols. This ratio varies dependant on the aerosol origin and the chemical processing in the atmosphere. Atmospheric observations have shown that as OA and its precursor gases age in the atmosphere, it leads to the formation of more oxidized (O:C atomic ratio 0.6 to 0.8), less volatile and less hydrophobic compounds (particle growth factor at 95% relative humidity of 0.16 to 0.20) that have more similar properties than fresh aerosols. While reported OM:OC ratios observed over USA range between 1.29 and 1.95, indicating significant contribution of local pollution sources to the OC in that region, high O/C ratio associated with a high OM/OC ratio of 2.2 has been also observed for the summertime East Mediterranean aged aerosol. In global models, the OM/OC ratio is either calculated for specific compounds or estimated for compound groups. In the present study, we review OM/OC observations and compare them with simulations from a variety of models that contributed to the AEROCOM exercise. We evaluate the chemical processing level of atmospheric aerosols simulated by the models. A total of 32 global chemistry transport models are considered in this study with variable complexity of the representation of OM/OC ratio in the OA. The analysis provides an integrated view of the OM/OC ratio in the global atmosphere and of the accuracy of its representation in the global models. Implications for atmospheric chemistry and climate simulations are discussed.

  20. Global Intercomparison of 12 Land Surface Heat Flux Estimates

    NASA Technical Reports Server (NTRS)

    Jimenez, C.; Prigent, C.; Mueller, B.; Seneviratne, S. I.; McCabe, M. F.; Wood, E. F.; Rossow, W. B.; Balsamo, G.; Betts, A. K.; Dirmeyer, P. A.; Fisher, J. B.; Jung, M.; Kanamitsu, M.; Reichle, R. H.; Reichstein, M.; Rodell, M.; Sheffield, J.; Tu, K.; Wang, K.

    2011-01-01

    A global intercomparison of 12 monthly mean land surface heat flux products for the period 1993-1995 is presented. The intercomparison includes some of the first emerging global satellite-based products (developed at Paris Observatory, Max Planck Institute for Biogeochemistry, University of California Berkeley, University of Maryland, and Princeton University) and examples of fluxes produced by reanalyses (ERA-Interim, MERRA, NCEP-DOE) and off-line land surface models (GSWP-2, GLDAS CLM/ Mosaic/Noah). An intercomparison of the global latent heat flux (Q(sub le)) annual means shows a spread of approx 20 W/sq m (all-product global average of approx 45 W/sq m). A similar spread is observed for the sensible (Q(sub h)) and net radiative (R(sub n)) fluxes. In general, the products correlate well with each other, helped by the large seasonal variability and common forcing data for some of the products. Expected spatial distributions related to the major climatic regimes and geographical features are reproduced by all products. Nevertheless, large Q(sub le)and Q(sub h) absolute differences are also observed. The fluxes were spatially averaged for 10 vegetation classes. The larger Q(sub le) differences were observed for the rain forest but, when normalized by mean fluxes, the differences were comparable to other classes. In general, the correlations between Q(sub le) and R(sub n) were higher for the satellite-based products compared with the reanalyses and off-line models. The fluxes were also averaged for 10 selected basins. The seasonality was generally well captured by all products, but large differences in the flux partitioning were observed for some products and basins.

  1. The global and local stellar mass assembly histories of galaxies from the MaNGA survey

    NASA Astrophysics Data System (ADS)

    Ibarra-Medel, H. J.; Sánchez,, S. F.; Avila-Reese, V.; Hernández-Toledo, H. M., J.

    2016-06-01

    By means of the fossil record method implemented through Pipe3D we reconstruct the global and radial stellar mass growth histories (MGHs) of a large sample of galaxies in the mass range 10^{8.5}M⊙-10^{11.5}M⊙ from the MaNGA survey. We find that: (1) The main driver of the global MGHs is mass, with more massive galaxies assembling their masses earlier (downsizing). (2) For most galaxies in their late evolutionary stages, the innermost regions formed earlier than the outermost ones (inside-out). This behaviour is stronger for blue/late-type galaxies.

  2. Optimal Estimates of Global Terrestrial GPP from Fluorescence and DGVMs

    NASA Astrophysics Data System (ADS)

    Parazoo, Nicholas; Bowman, Kevin; Fisher, Joshua; Frankenberg, Christian; Jones, Dylan; Cescatti, Alessandro; Perez-Priego, Oscar; Wohlfahrt, Georg; Montagnani, Leonardo

    2014-05-01

    Changes in the processes that control terrestrial carbon uptake are highly uncertain but likely to have a significant influence on future atmospheric CO2 levels. RECCAP aims to improve process understanding by reconciling fluxes from top-down CO2 inversions and bottom-up estimates from an ensemble of DGVMs. As these models are typically used in projections of climate change a key part of this effort is benchmarking models and evaluating drivers of net carbon exchange within the current climate. Of particular importance are the spatial distribution and time rate of change of GPP. Recent advances in the remote sensing of solar-induced chlorophyll fluorescence opens up a new possibility to directly measure planetary photosynthesis on spatially resolved scales. Here, we discuss a new methodology for estimating GPP and uncertainty from an optimal combination of an ensemble of DGVMs from the TRENDY project with satellite-based fluorescence observations from GOSAT. Prior uncertainty is estimated from the spread of DGVMs and updated through assimilation of fluorescence. We evaluate optimized fluxes against flux tower data in N. America, Europe, and S. America, benchmark TRENDY models using updated uncertainty estimates, and examine changes in the structure of the seasonal cycle. We find this methodology provides a novel way to evaluate models used in climate projections.

  3. On the Global Transport of Moisture: Comparison of Different Estimators

    NASA Technical Reports Server (NTRS)

    Haskins, R.; Fetzer, E.; Barnett, T.; Tyree, M.; Roeckner, E.

    1996-01-01

    An intercomparison is made between vertically integrated water vapor flux estimates from the NASA reanalysis product, and from two versions of an atmospheric general circulation model (AGCM) forced only by observed sea surface temperature (SST). The period of comparison was from March 1985-February 1991 plus data from the U.S. flood in 1993.

  4. Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis

    NASA Astrophysics Data System (ADS)

    Licquia, Timothy C.; Newman, Jeffrey A.

    2015-06-01

    We present improved estimates of several global properties of the Milky Way, including its current star formation rate (SFR), the stellar mass contained in its disk and bulge+bar components, as well as its total stellar mass. We do so by combining previous measurements from the literature using a hierarchical Bayesian (HB) statistical method that allows us to account for the possibility that any value may be incorrect or have underestimated errors. We show that this method is robust to a wide variety of assumptions about the nature of problems in individual measurements or error estimates. Ultimately, our analysis yields an SFR for the Galaxy of {{\\dot{M}}\\star }=1.65+/- 0.19 {{M}⊙ } y{{r}-1}, assuming a Kroupa initial mass function (IMF). By combining HB methods with Monte Carlo simulations that incorporate the latest estimates of the Galactocentric radius of the Sun, R0, the exponential scale length of the disk, Ld, and the local surface density of stellar mass, {{Σ}\\star }({{R}0}), we show that the mass of the Galactic bulge+bar is M\\star B=0.91+/- 0.07× {{10}10} {{M}⊙ }, the disk mass is M\\star D=5.17+/- 1.11× {{10}10} {{M}⊙ }, and their combination yields a total stellar mass of {{M}\\star }=6.08+/- 1.14× {{10}10} {{M}⊙ } (assuming a Kroupa IMF and an exponential disk profile). This analysis is based upon a new compilation of literature bulge mass estimates, normalized to common assumptions about the stellar IMF and Galactic disk properties, presented herein. We additionally find a bulge-to-total mass ratio for the Milky Way of B/T=0.150-0.019+0.028 and a specific SFR of {{\\dot{M}}\\star }/{{M}\\star }=2.71+/- 0.59× {{10}-11} yr-1.

  5. The estimation of masses of individual galaxies in clusters of galaxies.

    NASA Technical Reports Server (NTRS)

    Wolf, R. A.; Bahcall, J. N.

    1972-01-01

    Three different methods of estimating masses are discussed. The 'density method' is based on the analysis of the density distribution of galaxies around the object whose mass is to be found. The 'bound-galaxy method' gives estimates of the mass of a double, triple, or quadruple system from analysis of the orbital motion of the components. The 'virial method' utilizes the formulas derived for the second method to obtain estimates of the virial-theorem masses of whole clusters, and thus to obtain upper limits on the mass of an individual galaxy in a cluster. The analytic formulas are developed and compared with computer experiments, and some applications are given.

  6. Mass and Composition of the Continental Crust Estimated Using the CRUST2.0 Model

    NASA Astrophysics Data System (ADS)

    Peterson, B. T.; Depaolo, D. J.

    2007-12-01

    The mass, age, and chemical composition of the continental crust are fundamental data for understanding Earth differentiation. The inaccessibility of most of the volume of the crust requires that inferences be made about geochemistry using seismic and heat flow data, with additional constraints provided by scarce lower crustal samples (Rudnick and Fountain, Rev. Geophys., 1995; Rudnick and Gao, Treatise on Geochem., 2003). The global crustal seismic database CRUST2.0 (Bassin, et al., EOS, 2000; Mooney, et al., JGR, 1998; hereafter C2) provides a useful template with which the size and composition of the continents can be assessed, and may be a useful vehicle to organize and analyze diverse geochemical data. We have used C2 to evaluate the modern mass and composition of the continental crust and their uncertainties, and explored our results in the context of global mass balances, such as continents versus depleted mantle. The major source of uncertainty comes from the definition of "continent." The ultimate constraint is the total mass of Earth's crust (oceanic + continental), which, from C2, is 2.77 (in units of 1022 kg). Using crustal thickness as a definition of continent, the mass of continental crust (CC) is 2.195 if the minimum thickness is 12-18km, 2.085 for 22.5km, 2.002 for 25km, and 1.860 for 30km. These numbers include all sediment as continental crust. Using C2 definitions to distinguish oceanic and continental crust (and including oceanic plateaus which contain some continental crust), we calculate the CC mass as 2.171. To estimate chemical composition, we use the C2 reservoir masses. For minimum thickness of 22.5km, C2 yields the proportions 0.016 oceanic sediment, 0.038 continental sediment, 0.321 upper crust, 0.326 middle crust, 0.299 lower crust. Upper, middle, and lower crust are assigned compositions from Rudnick and Gao (2003), continental sediments are assigned upper crust composition, and oceanic sediments are assigned GLOSS composition (Plank

  7. Estimation of Subdaily Polar Motion with the Global Positioning System During the Spoch '92 Campaign

    NASA Technical Reports Server (NTRS)

    Ibanez-Meier, R.; Freedman, A. P.; Herring, T. A.; Gross, R. S.; Lichten, S. M.; Lindqwister, U. J.

    1994-01-01

    Data collected over six days from a worldwide Global Positioning System (GPS) tracking network during the Epoch '92 campaign are used to estimate variations of the Earth's pole position every 30 minutes.

  8. Uncertainty Estimation of Global Precipitation Measurement through Objective Validation Strategy

    NASA Astrophysics Data System (ADS)

    KIM, H.; Utsumi, N.; Seto, S.; Oki, T.

    2014-12-01

    Since Tropical Rainfall Measuring Mission (TRMM) has been launched in 1997 as the first satellite mission dedicated to measuring precipitation, the spatiotemporal gaps of precipitation observation have been filled significantly. On February 27th, 2014, Dual-frequency Precipitation Radar (DPR) satellite has been launched as a core observatory of Global Precipitation Measurement (GPM), an international multi-satellite mission aiming to provide the global three hourly map of rainfall and snowfall. In addition to Ku-band, Ka-band radar is newly equipped, and their combination is expected to introduce higher precision than the precipitation measurement of TRMM/PR. In this study, the GPM level-2 orbit products are evaluated comparing to various precipitation observations which include TRMM/PR, in-situ data, and ground radar. In the preliminary validation over intercross orbits of DPR and TRMM, Ku-band measurements in both satellites shows very close spatial pattern and intensity, and the DPR is capable to capture broader range of precipitation intensity than of the TRMM. Furthermore, we suggest a validation strategy based on 'objective classification' of background atmospheric mechanisms. The Japanese 55-year Reanalysis (JRA-55) and auxiliary datasets (e.g., tropical cyclone best track) is used to objectively determine the types of precipitation. Uncertainty of abovementioned precipitation products is quantified as their relative differences and characterized for different precipitation mechanism. Also, it is discussed how the uncertainty affects the synthesis of TRMM and GPM for a long-term satellite precipitation observation records which is internally consistent.

  9. Exposure assessment for estimation of the global burden of disease attributable to outdoor air pollution

    PubMed Central

    Brauer, Michael; Amann, Markus; Burnett, Rick T.; Cohen, Aaron; Dentener, Frank; Ezzati, Majid; Henderson, Sarah B.; Krzyzanowski, Michal; Martin, Randall V.; Van Dingenen, Rita; van Donkelaar, Aaron; Thurston, George D.

    2014-01-01

    Ambient air pollution is associated with numerous adverse health impacts. Previous assessments of global attributable disease burden have been limited to urban areas or by coarse spatial resolution of concentration estimates. Recent developments in remote sensing, global chemical-transport models, and improvements in coverage of surface measurements facilitate virtually complete spatially resolved global air pollutant concentration estimates. We combined these data to generate global estimates of long- term average ambient concentrations of fine particles (PM2.5) and ozone at 0.1° × 0.1° spatial resolution for 1990 and 2005. In 2005, 89% of the world’s population lived in areas where the World Health Organization Air Quality Guideline of 10 μg/m3 PM2.5 (annual average) was exceeded. Globally, 32% of the population lived in areas exceeding the WHO Level 1 Interim Target of 35 μg/m3; driven by high proportions in East (76%) and South (26%) Asia. The highest seasonal ozone levels were found in North and Latin America, Europe, South and East Asia, and parts of Africa. Between 1990 and 2005 a 6% increase in global population-weighted PM2.5 and a 1% decrease in global population- weighted ozone concentrations was apparent, highlighted by increased concentrations in East, South and Southeast Asia and decreases in North America and Europe. Combined with spatially resolved population distributions, these estimates expand the evaluation of the global health burden associated with outdoor air pollution. PMID:22148428

  10. Estimated global exportations of Zika virus infections via travellers from Brazil from 2014 to 2015.

    PubMed

    Quam, Mikkel B; Wilder-Smith, Annelies

    2016-06-01

    The ongoing Zika pandemic in Latin America illustrates a potential source for further globalized spread. Here, we assessed global travel-related Zika virus exportations from Brazil during the initial year of the epidemic. Similar to subsequent national notifications, we estimated 584-1786 exported Zika cases from Brazil occurred September 2014-August 2015. PMID:27601533

  11. Similar negative impacts of temperature on global wheat yield estimated by three independent methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential impact of global temperature change on global wheat production has recently been assessed with different methods, scaling and aggregation approaches. Here we show that grid-based simulations, point-based simulations, and statistical regressions produce similar estimates of temperature ...

  12. Non-Tidal Non-Seasonal Oceanic Mass Redistribution Estimated from the TOPEX/Poseidon Observation

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.; Au, A. Y.; Chen, Jian-Li; Smith, David E. (Technical Monitor)

    2000-01-01

    Topex/Poseidon altimetry data are used to estimate the non-tidal mass redistribution as a function of space-time. The goal is to study the contribution of ocean circulations in the geodynamic effects including Earth's rotational and gravitational variations. We examine the non-seasonal anomalies at monthly sampling rate over the T/P span of eight years, concentrating especially on interannual variabilities. Since the sea-surface height data obtained from altimetry is the combined effect of steric change (primarily thermal effect) and the mass flux, and because the former has zero contribution to the geodynamic effects, one needs to do a so-called steric correction by removing from the altimetry data the steric contributions. We achieve it using multiyear monthly sea-surface temperature maps, together with monthly "climatology" for mixed-layer depth maps for mean-months of the year. We analyze both sets of the altimetry data and the steric correction data using the empirical orthogonal function/principal component analysis (in which we take care of issues associated with the area-weighting and non-zero mean), and examine the most important modes, either globally or regionally. In particular, the ENSO in the tropical Pacific/Indian Oceans exhibits the most prominent pattern. The net mass transport after the steric correction can then be compared with: (1) ocean general circulation model outputs for the same period of time (such as from POCM-4B); (2) non-atmospheric Earth rotation variations obtained from space geodesy data and atmospheric angular momentum data; (3) non-atmospheric low-degree gravitational variations from satellite-laser-ranging observations and global atmospheric data.

  13. A Global Ocean State Estimate at the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Amrhein, D. E.; Wunsch, C. I.

    2015-12-01

    Many features of Earth's climate at the Last Glacial Maximum (LGM, ca. 20,000 years ago) remain a mystery, including the role of the ocean circulation in transporting thermal energy, salinity, and other tracers. Most efforts at reconstructing the ocean state during the LGM have relied either upon integrations of general circulation models under prescribed LGM boundary conditions or the interpretation of climate proxy records without explicit physical constraints. Here we describe a global, primitive equation simulation of the LGM ocean with boundary conditions (wind, surface air temperature, and other atmospheric variables) and mixing parameters derived by a least-squares fit of an ocean general circulation model to observations of deep ocean stable isotopes and sea surface temperatures at the LGM.

  14. Assimilation of GRACE-derived oceanic mass distributions with a global ocean circulation model

    NASA Astrophysics Data System (ADS)

    Saynisch, J.; Bergmann-Wolf, I.; Thomas, M.

    2015-02-01

    To study the sub-seasonal distribution and generation of ocean mass anomalies, Gravity Recovery and Climate Experiment (GRACE) observations of daily and monthly resolution are assimilated into a global ocean circulation model with an ensemble-based Kalman-Filter technique. The satellite gravimetry observations are processed to become time-variable fields of ocean mass distribution. Error budgets for the observations and the ocean model's initial state are estimated which contain the full covariance information. The consistency of the presented approach is demonstrated by increased agreement between GRACE observations and the ocean model. Furthermore, the simulations are compared with independent observations from 54 bottom pressure recorders. The assimilation improves the agreement to high-latitude recorders by up to 2 hPa. The improvements are caused by assimilation-induced changes in the atmospheric wind forcing, i.e., quantities not directly observed by GRACE. Finally, the use of the developed Kalman-Filter approach as a destriping filter to remove artificial noise contaminating the GRACE observations is presented.

  15. Estimates of radiated energy from global shallow subduction zone earthquakes

    NASA Astrophysics Data System (ADS)

    Bilek, S. L.; Lay, T.; Ruff, L.

    2002-12-01

    Previous studies used seismic energy to moment ratios for datasets of large earthquakes as a useful discriminant for tsunami earthquakes. We extend this idea of a "slowness" discriminant to a large dataset of subduction zone underthrusting earthquakes. We determined estimates of energy release in these shallow earthquakes using a large dataset of source time functions. This dataset contains source time functions for 418 shallow (< 70 km depth) earthquakes ranging from Mw 5.5 - 8.0 from 14 circum-Pacific subduction zones. Also included are tsunami earthquakes for which source time functions are available. We calculate energy using two methods, a substitution of a simplified triangle and integration of the original source time function. In the first method, we use a triangle substitution of peak moment and duration to find a minimum estimate of energy. The other method incorporates more of the source time function information and can be influenced by source time function complexity. We examine patterns in source time function complexity with respect to the energy estimates. For comparison with other earthquake parameters, it is useful to remove the effect of seismic moment on the energy estimates. We use the seismic energy to moment ratio (E/Mo) to highlight variations with depth, moment, and subduction zone. There is significant scatter in this ratio using both methods of energy calculation. We observe a slight increase in E/Mo with increasing Mw. There is not much variation in E/Mo with depth seen in entire dataset. However, a slight increase in E/Mo with depth is apparent in a few subduction zones such as Alaska, Central America, and Peru. An average E/Mo of 5x10e-6 roughly characterizes this shallow earthquake dataset, although with a factor of 10 scatter. This value is within about a factor of 2 of E/Mo ratios determined by Choy and Boatwright (1995). Tsunami earthquakes suggest an average E/Mo of 2x10e-7, significantly lower than the average for the shallow

  16. Anthropogenic CO2 estimates in the Southern Ocean: Storage partitioning in the different water masses

    NASA Astrophysics Data System (ADS)

    Pardo, Paula C.; Pérez, F. F.; Khatiwala, S.; Ríos, A. F.

    2014-01-01

    The role of the Southern Ocean (SO) remains a key issue in our understanding of the global carbon cycle and for predicting future climate change. A number of recent studies suggest that 30 to 40% of ocean uptake of anthropogenic carbon (CANT) occurs in the SO, accompanied by highly efficient transport of CANT by intermediate-depth waters out of that region. In contrast, storage of CANT in deep and bottom layers is still an open question. Significant discrepancies can be found between results from several indirect techniques and ocean models. Even though reference methodologies state that CANT concentrations in deep and bottom layers of the SO are negligible, recent results from tracer-based methods and ocean models as well as accurate measurements of 39Ar, CCl4 and CFCs along the continental slope and in the Antarctic deep and bottom waters contradict this conclusion. The role of the SO in the uptake, storage and transport of CANT has proved to be really important for the global ocean and there is a need for agreement between the different techniques. A CO2-data-based ("back-calculation") method, the CT0 method, was developed with the aim of obtaining more accurate CANT concentration and inventory estimates in the SO region (south of 45°S). Data from the GLODAP (Global Ocean Data Analysis Project) and CARINA databases were used. The CT0 method tries to reduce at least two of the main caveats attributed to the back-calculation methods: the need for a better definition of water mass mixing and, most importantly, the unsteady state of the air-sea CO2 disequilibrium (ΔCdis) term. Water mass mixing was computed on the basis of results from an extended Optimum Multi-Parametric (eOMP) analysis applied to the main water masses of the SO. Recently published parameterizations were used to obtain more reliable values of ΔCdis and also of preformed alkalinity. The variability of the ΔCdis term (δCdis) was approximated using results from an ocean carbon cycle model

  17. Global surface density of water mass variations by using a two-step inversion by cumulating daily satellite gravity information

    NASA Astrophysics Data System (ADS)

    Ramillien, Guillaume; Frappart, Frédéric; Seoane, Lucia

    2016-04-01

    We propose a new method to produce time series of global maps of surface mass variations by progressive integration of daily geopotential variations measured by orbiting satellites. In the case of the GRACE mission, these geopotential variations can be determined from very accurate inter-satellite K-Band Range Rate (KBRR) measurements of 5-second daily orbits. In particular, the along-track gravity contribution of hydrological mass changes is extracted by removing de-aliasing models for static field, atmosphere, oceans mass variations (including periodical tides), as well as polar movements. Our determination of surface mass sources is composed of two successive dependent Kalman filter stages. The first one consists of reducing the satellite-based potential anomalies by adjusting the longest spatial wavelengths (i.e., low-degree spherical harmonics lower than 2). In the second stage, the residual potential anomalies from the previous stage are used to recover surface mass density changes - in terms of Equivalent-Water Height (EWH) - over a global network of juxtaposed triangular elements. These surface tiles of ~100,000 km x km (or equivalently 330 km by 330 km) are defined to be of equal areas over the terrestrial sphere. However they can be adapted to the local geometry of the surface mass. Our global approach was tested by inverting geopotential data, and successfully applied to estimate time-varying surface mass densities from real GRACE-based residuals. This strategy of combined Kalman filter-type inversions can also be useful for exploring the possibility of improving time and space resolutions for ocean and land studies that would be hopefully brought by future low altitude geodetic missions.

  18. New estimates of silicate weathering rates and their uncertainties in global rivers

    NASA Astrophysics Data System (ADS)

    Moon, Seulgi; Chamberlain, C. P.; Hilley, G. E.

    2014-06-01

    This study estimated the catchment- and global-scale weathering rates of silicate rocks from global rivers using global compilation datasets from the GEMS/Water and HYBAM. These datasets include both time-series of chemical concentrations of major elements and synchronous discharge. Using these datasets, we first examined the sources of uncertainties in catchment and global silicate weathering rates. Then, we proposed future sampling strategies and geochemical analyses to estimate accurate silicate weathering rates in global rivers and to reduce uncertainties in their estimates. For catchment silicate weathering rates, we considered uncertainties due to sampling frequency and variability in river discharge, concentration, and attribution of weathering to different chemical sources. Our results showed that uncertainties in catchment-scale silicate weathering rates were due mostly to the variations in discharge and cation fractions from silicate substrates. To calculate unbiased silicate weathering rates accounting for the variations from discharge and concentrations, we suggest that at least 10 and preferably ∼40 temporal chemical data points with synchronous discharge from each river are necessary. For the global silicate weathering rate, we examined uncertainties from infrequent sampling within an individual river, the extrapolation from limited rivers to a global flux, and the inverse model selections for source differentiation. For this weathering rate, we found that the main uncertainty came from the extrapolation to the global flux and the model configurations of source differentiation methods. This suggests that to reduce the uncertainties in the global silicate weathering rates, coverage of synchronous datasets of river chemistry and discharge to rivers from tectonically active regions and volcanic provinces must be extended, and catchment-specific silicate end-members for those rivers must be characterized. With current available synchronous datasets, we

  19. Estimating inter-annual runoff variability from global hydroclimatic data

    NASA Astrophysics Data System (ADS)

    Peel, Murray; McMahon, Thomas; Finlayson, Brian

    2016-04-01

    Inter-annual variability of runoff, measured by the coefficient of variation of annual runoff (RCv), is an important constraint on reservoir yield and storage size for water resources management. For a catchment with a fixed storage capacity, any increase in reservoir inflow RCv translates into reduced reservoir yield for a given reliability of supply. Developing an improved understanding of the physical influences on inter-annual runoff variability around the world and how these may change in future is of vital importance to achieving on-going robust water and catchment management. Here we take a large-scale Comparative Hydrology approach to develop empirical relationships for RCv using a global hydroclimatic data set of 588 catchments. Empirical RCv relationships are developed for the World and catchments experiencing predominantly (≥75% catchment area) tropical, arid, temperate or cold climate types. The RCv relationships are developed specifically using non-streamflow based predictor variables so they can be used for predicting RCv in ungauged basins (the PUB problem - Prediction in Ungauged Basins) and or ungauged climates (the PUC problem - Prediction in Ungauged Climates) if past or future projections of the required predictor variables are available. Empirical relationship predictor variables are based on precipitation, evaporative demand, vegetation and topography. Key variables that contribute to explaining RCv in each relationship will be assessed to identify the dominant drivers of RCv and how the contribution of those drivers varies between regions and climate types, with particular focus on inter-annual climate variability.

  20. Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients

    PubMed Central

    Golden, Christopher D.; Mozaffarian, Dariush

    2016-01-01

    Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model—the Global Expanded Nutrient Supply (GENuS) model—to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961–2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent

  1. Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

    PubMed

    Smith, Matthew R; Micha, Renata; Golden, Christopher D; Mozaffarian, Dariush; Myers, Samuel S

    2016-01-01

    Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS) model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent

  2. Sensitivity of Simulated Global Ocean Carbon Flux Estimates to Forcing by Reanalysis Products

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Casey, Nancy W.; Rousseaux, Cecile S.

    2015-01-01

    Reanalysis products from MERRA, NCEP2, NCEP1, and ECMWF were used to force an established ocean biogeochemical model to estimate air-sea carbon fluxes (FCO2) and partial pressure of carbon dioxide (pCO2) in the global oceans. Global air-sea carbon fluxes and pCO2 were relatively insensitive to the choice of forcing reanalysis. All global FCO2 estimates from the model forced by the four different reanalyses were within 20% of in situ estimates (MERRA and NCEP1 were within 7%), and all models exhibited statistically significant positive correlations with in situ estimates across the 12 major oceanographic basins. Global pCO2 estimates were within 1% of in situ estimates with ECMWF being the outlier at 0.6%. Basin correlations were similar to FCO2. There were, however, substantial departures among basin estimates from the different reanalysis forcings. The high latitudes and tropics had the largest ranges in estimated fluxes among the reanalyses. Regional pCO2 differences among the reanalysis forcings were muted relative to the FCO2 results. No individual reanalysis was uniformly better or worse in the major oceanographic basins. The results provide information on the characterization of uncertainty in ocean carbon models due to choice of reanalysis forcing.

  3. Global estimation of CO emissions using three sets of satellite data for burned area

    NASA Astrophysics Data System (ADS)

    Jain, Atul K.

    Using three sets of satellite data for burned areas together with the tree cover imagery and a biogeochemical component of the Integrated Science Assessment Model (ISAM) the global emissions of CO and associated uncertainties are estimated for the year 2000. The available fuel load (AFL) is calculated using the ISAM biogeochemical model, which accounts for the aboveground and surface fuel removed by land clearing for croplands and pasturelands, as well as the influence on fuel load of various ecosystem processes (such as stomatal conductance, evapotranspiration, plant photosynthesis and respiration, litter production, and soil organic carbon decomposition) and important feedback mechanisms (such as climate and fertilization feedback mechanism). The ISAM estimated global total AFL in the year 2000 was about 687 Pg AFL. All forest ecosystems account for about 90% of the global total AFL. The estimated global CO emissions based on three global burned area satellite data sets (GLOBSCAR, GBA, and Global Fire Emissions Database version 2 (GFEDv2)) for the year 2000 ranges between 320 and 390 Tg CO. Emissions from open fires are highest in tropical Africa, primarily due to forest cutting and burning. The estimated overall uncertainty in global CO emission is about ±65%, with the highest uncertainty occurring in North Africa and Middle East region (±99%). The results of this study suggest that the uncertainties in the calculated emissions stem primarily from the area burned data.

  4. An improved technique for global solar radiation estimation using numerical weather prediction

    NASA Astrophysics Data System (ADS)

    Shamim, M. A.; Remesan, R.; Bray, M.; Han, D.

    2015-07-01

    Global solar radiation is the driving force in hydrological cycle especially for evapotranspiration (ET) and is quite infrequently measured. This has led to the reliance on indirect techniques of estimation for data scarce regions. This study presents an improved technique that uses information from a numerical weather prediction (NWP) model (National Centre for Atmospheric Research NCAR's Mesoscale Meteorological model version 5 MM5), for the determination of a cloud cover index (CI), a major factor in the attenuation of the incident solar radiation. The cloud cover index (CI) together with the atmospheric transmission factor (KT) and output from a global clear sky solar radiation were then used for the estimation of global solar radiation for the Brue catchment located in the southwest of England. The results clearly show an improvement in the estimated global solar radiation in comparison to the prevailing approaches.

  5. Estimates of Particulate Mass in Multi Canister Overpacks (MCO)

    SciTech Connect

    SLOUGHTER, J.P.

    2000-02-16

    High, best estimate, and low values are developed for particulate inventories within MCO baskets that have been loaded with freshly cleaned fuel assemblies and scrap. These per-basket estimates are then applied to all anticipated MCO payload configurations to identify which configurations are bounding for each type of particulate. Finally the resulting bounding and nominal values for residual particulates are combined with corresponding values [from other documents] for particulates that may be generated by corrosion of exposed uranium after the fuel has been cleaned. The resulting rounded nominal estimate for a typical MCO after 40 years of storage is 8 kg. The estimate for a bounding total particulate case MCO is that it may contain up to 64 kg of particulate after 40 years of storage.

  6. A Probabilistic Mass Estimation Algorithm for a Novel 7- Channel Capacitive Sample Verification Sensor

    NASA Technical Reports Server (NTRS)

    Wolf, Michael

    2012-01-01

    A document describes an algorithm created to estimate the mass placed on a sample verification sensor (SVS) designed for lunar or planetary robotic sample return missions. A novel SVS measures the capacitance between a rigid bottom plate and an elastic top membrane in seven locations. As additional sample material (soil and/or small rocks) is placed on the top membrane, the deformation of the membrane increases the capacitance. The mass estimation algorithm addresses both the calibration of each SVS channel, and also addresses how to combine the capacitances read from each of the seven channels into a single mass estimate. The probabilistic approach combines the channels according to the variance observed during the training phase, and provides not only the mass estimate, but also a value for the certainty of the estimate. SVS capacitance data is collected for known masses under a wide variety of possible loading scenarios, though in all cases, the distribution of sample within the canister is expected to be approximately uniform. A capacitance-vs-mass curve is fitted to this data, and is subsequently used to determine the mass estimate for the single channel s capacitance reading during the measurement phase. This results in seven different mass estimates, one for each SVS channel. Moreover, the variance of the calibration data is used to place a Gaussian probability distribution function (pdf) around this mass estimate. To blend these seven estimates, the seven pdfs are combined into a single Gaussian distribution function, providing the final mean and variance of the estimate. This blending technique essentially takes the final estimate as an average of the estimates of the seven channels, weighted by the inverse of the channel s variance.

  7. Estimation of body mass index from the metrics of the first metatarsal

    NASA Astrophysics Data System (ADS)

    Dunn, Tyler E.

    Estimation of the biological profile from as many skeletal elements as possible is a necessity in both forensic and bioarchaeological contexts; this includes non-standard aspects of the biological profile, such as body mass index (BMI). BMI is a measure that allows for understanding of the composition of an individual and is traditionally divided into four groups: underweight, normal weight, overweight, and obese. BMI estimation incorporates both estimation of stature and body mass. The estimation of stature from skeletal elements is commonly included into the standard biological profile but the estimation of body mass needs to be further statistically validated to be consistently included. The bones of the foot, specifically the first metatarsal, may have the ability to estimate BMI given an allometric relationship to stature and the mechanical relationship to body mass. There are two commonly used methods for stature estimation, the anatomical method and the regression method. The anatomical method takes into account all of the skeletal elements that contribute to stature while the regression method relies on the allometric relationship between a skeletal element and living stature. A correlation between the metrics of the first metatarsal and living stature has been observed, and proposed as a method for valid stature estimation from the boney foot (Byers et al., 1989). Body mass estimation from skeletal elements relies on two theoretical frameworks: the morphometric and the mechanical approaches. The morphometric approach relies on the size relationship of the individual to body mass; the basic relationship between volume, density, and weight allows for body mass estimation. The body is thought of as a cylinder, and in order to understand the volume of this cylinder the diameter is needed. A commonly used proxy for this in the human body is skeletal bi-iliac breadth from rearticulated pelvic girdle. The mechanical method of body mass estimation relies on the

  8. Mass screening for neuroblastoma and estimation of costs.

    PubMed

    Nishi, M; Miyake, H; Takeda, T; Takasugi, N; Hanai, J; Kawai, T

    1991-01-01

    On the basis of epidemiological data and medical costs for patients with neuroblastoma, we have calculated the cost of mass screening for neuroblastoma with high performance liquid chromatography (HPLC) compared to the cost when it is not performed. If the sensitivity of the mass screening is 80% and 22,000 infants are screened annually the cost will be 27,809,000 yen ($191,800). If mass is not performed, the cost will be 28,446,000 yen ($196,200). The difference in cost (637,000 yen or $4,400) is fairly small. If the sensitivity is 75% and 16,500 infants are screened, the difference is also small (174,000 yen or $1,200). Therefore, mass screening with the HPLC method will not be an undue financial burden. But re-screening at an older age will be done with less financially favorable results, considering that the sensitivity may not be as high as that of the first screening and that mothers are somewhat reluctant about re-screening. The balance of the cost of mass screening by qualitative methods may also be less favorable, since the detection rate is low. PMID:1957600

  9. Estimating mass of crushed limestone particles from 2D images

    NASA Astrophysics Data System (ADS)

    Banta, Larry E.; Cheng, Ken; Zaniewski, John P.

    2002-02-01

    In the construction of asphalt pavements, the stability of the asphalt is determined in large part by the gradation, or size distribution of the mineral aggregates that make up the matrix. Gradation is specified on the basis of sieve sizes and percent passing, where the latter is a cumulative measure of the mass of the aggregate passing the sieve as fraction of the total mass in the batch. In this paper, an approach for predicting particle mass based on 2D electronic images is explored. Images of crushed limestone aggregates were acquired using backlighting to create silhouettes. A morphological erosion process was used to separate touching and overlapping particles. Useful features of the particle silhouettes, such as area, centroid and shape descriptors were collected. Several dimensionless parameters were defined and were used as regressor variables in a multiple linear regression model to predict particle mass. Regressor coefficients were found by fitting to a sample of 501 particles ranging in size from 4.75 mm < particle sieve size < 25 mm. When tested against a different aggregate sample, the model predicted the mass of the batch to within +/- 2%.

  10. Diagnostic Up-scaling of GPP from Eddy Covariance to Global Estimates

    NASA Astrophysics Data System (ADS)

    Tomelleri, E.; Beer, C.; Carvalhais, N.; Jung, M.; Papale, D.; Reichstein, M.; Ciais, P.; Peylin, P.; Pis, F.

    2009-12-01

    The uptake of atmospheric CO2 by plant photosynthesis is the largest global carbon flux and drives all terrestrial carbon cycle processes. While the photosynthesis processes at the leaf and canopy levels are quite well understood, so far only very crude estimates of its global integral, the Gross Primary Production (GPP) can be found in the literature. Existing estimates have been lacking sound empirical basis. Reasons for such limitations lie in the absence of direct estimates of ecosystem-level GPP and methodological difficulties in scaling local carbon flux measurements to global scale across heterogeneous vegetation. Here, we present global estimates of GPP based on different diagnostic approaches. All these up-scaling schemes integrated high-resolution remote sensing products, such as land cover, the fraction of photosynthetically active radiation (fAPAR) and leaf-area index, with carbon flux measurements from the global network of eddy covariance stations (FLUXNET). In addition, meteorological datasets from diverse sources and river runoff observations were used. All the above-mentioned approaches were also capable of estimating uncertainties. With six novel or newly parameterized and highly diverse up-scaling schemes we consistently estimated a global GPP of 122 Pg C y-1. This value is 5 % higher than estimates from inversions of 18O and CO2 atmospheric concentration. In the quantification of the total uncertainties, we considered uncertainties arising from the measurement technique and data processing (i.e. partitioning into GPP and respiration). Furthermore, we accounted for the uncertainties of drivers and the structural uncertainties of the extrapolation approach. The total propagation led to a global uncertainty of 15 % of the mean value. Although our mean GPP estimate of 122 Pg C y-1 is similar to the previous postulate by Intergovernmental Panel on Climate Change in 2001, we estimated a different variability among ecoregions. The tropics accounted for

  11. Estimating the Global Clinical Burden of Plasmodium falciparum Malaria in 2007

    PubMed Central

    Hay, Simon I.; Okiro, Emelda A.; Gething, Peter W.; Patil, Anand P.; Tatem, Andrew J.; Guerra, Carlos A.; Snow, Robert W.

    2010-01-01

    Background The epidemiology of malaria makes surveillance-based methods of estimating its disease burden problematic. Cartographic approaches have provided alternative malaria burden estimates, but there remains widespread misunderstanding about their derivation and fidelity. The aims of this study are to present a new cartographic technique and its application for deriving global clinical burden estimates of Plasmodium falciparum malaria for 2007, and to compare these estimates and their likely precision with those derived under existing surveillance-based approaches. Methods and Findings In seven of the 87 countries endemic for P. falciparum malaria, the health reporting infrastructure was deemed sufficiently rigorous for case reports to be used verbatim. In the remaining countries, the mapped extent of unstable and stable P. falciparum malaria transmission was first determined. Estimates of the plausible incidence range of clinical cases were then calculated within the spatial limits of unstable transmission. A modelled relationship between clinical incidence and prevalence was used, together with new maps of P. falciparum malaria endemicity, to estimate incidence in areas of stable transmission, and geostatistical joint simulation was used to quantify uncertainty in these estimates at national, regional, and global scales. Combining these estimates for all areas of transmission risk resulted in 451 million (95% credible interval 349–552 million) clinical cases of P. falciparum malaria in 2007. Almost all of this burden of morbidity occurred in areas of stable transmission. More than half of all estimated P. falciparum clinical cases and associated uncertainty occurred in India, Nigeria, the Democratic Republic of the Congo (DRC), and Myanmar (Burma), where 1.405 billion people are at risk. Recent surveillance-based methods of burden estimation were then reviewed and discrepancies in national estimates explored. When these cartographically derived national

  12. Added mass matrix estimation of beams partially immersed in water using measured dynamic responses

    NASA Astrophysics Data System (ADS)

    Liu, Fushun; Li, Huajun; Qin, Hongde; Liang, Bingchen

    2014-09-01

    An added mass matrix estimation method for beams partially immersed in water is proposed that employs dynamic responses, which are measured when the structure is in water and in air. Discrepancies such as mass and stiffness matrices between the finite element model (FEM) and real structure could be separated from the added mass of water by a series of correction factors, which means that the mass and stiffness of the FEM and the added mass of water could be estimated simultaneously. Compared with traditional methods, the estimated added mass correction factors of our approach will not be limited to be constant when FEM or the environment of the structure changed, meaning that the proposed method could reflect the influence of changes such as water depth, current, and so on. The greatest improvement is that the proposed method could estimate added mass of water without involving any water-related assumptions because all water influences are reflected in measured dynamic responses of the structure in water. A five degrees-of-freedom (dofs) mass-spring system is used to study the performance of the proposed scheme. The numerical results indicate that mass, stiffness, and added mass correction factors could be estimated accurately when noise-free measurements are used. Even when the first two modes are measured under the 5 percent corruption level, the added mass could be estimated properly. A steel cantilever beam with a rectangular section in a water tank at Ocean University of China was also employed to study the added mass influence on modal parameter identification and to investigate the performance of the proposed method. The experimental results demonstrated that the first two modal frequencies and mode shapes of the updated model match well with the measured values by combining the estimated added mass in the initial FEM.

  13. Skeletal Correlates for Body Mass Estimation in Modern and Fossil Flying Birds

    PubMed Central

    Field, Daniel J.; Lynner, Colton; Brown, Christian; Darroch, Simon A. F.

    2013-01-01

    Scaling relationships between skeletal dimensions and body mass in extant birds are often used to estimate body mass in fossil crown-group birds, as well as in stem-group avialans. However, useful statistical measurements for constraining the precision and accuracy of fossil mass estimates are rarely provided, which prevents the quantification of robust upper and lower bound body mass estimates for fossils. Here, we generate thirteen body mass correlations and associated measures of statistical robustness using a sample of 863 extant flying birds. By providing robust body mass regressions with upper- and lower-bound prediction intervals for individual skeletal elements, we address the longstanding problem of body mass estimation for highly fragmentary fossil birds. We demonstrate that the most precise proxy for estimating body mass in the overall dataset, measured both as coefficient determination of ordinary least squares regression and percent prediction error, is the maximum diameter of the coracoid’s humeral articulation facet (the glenoid). We further demonstrate that this result is consistent among the majority of investigated avian orders (10 out of 18). As a result, we suggest that, in the majority of cases, this proxy may provide the most accurate estimates of body mass for volant fossil birds. Additionally, by presenting statistical measurements of body mass prediction error for thirteen different body mass regressions, this study provides a much-needed quantitative framework for the accurate estimation of body mass and associated ecological correlates in fossil birds. The application of these regressions will enhance the precision and robustness of many mass-based inferences in future paleornithological studies. PMID:24312392

  14. A Simple Estimate of the Mass of the Positron.

    ERIC Educational Resources Information Center

    Jones, Goronwy Tudor

    1993-01-01

    Discusses a small part of the final state of a high-energy neutrino interaction: a head-on collision of a positron and a stationary electron. Provides a bubble chamber picture and describes the resulting particle effects. Uses momentum to determine the mass of the positron. (MVL)

  15. Significantly improving stellar mass and radius estimates: a new reference function for the Δν scaling relation

    NASA Astrophysics Data System (ADS)

    Guggenberger, Elisabeth; Hekker, Saskia; Basu, Sarbani; Bellinger, Earl

    2016-08-01

    The scaling relations between global asteroseismic observables and stellar properties are widely used to estimate masses and radii of stars exhibiting solar-like oscillations. Since the mass and radius of the Sun are known independently, the Sun is commonly used as a reference to scale to. However, the validity of the scaling relations depends on the homology between the star under study and the reference star. Solar-like oscillators span a wide range of masses and metallicities, as well as evolutionary phases. Most of these stars are therefore not homologous to the Sun. This leads to errors of up to 10% (5%) in mass (radius) when using the asteroseismic scaling relations with the Sun as the reference. In this paper we derive a reference function to replace the solar-reference value used in the large-frequency-separation scaling relation. Our function is the first that depends on both effective temperature and metallicity, and is applicable from the end of the main sequence to just above the bump on the red giant branch. This reference function improves the estimates of masses and radii determined through scaling relations by a factor of 2, i.e. allows masses and radii to be recovered with an accuracy of 5% and 2%, respectively.

  16. Significantly improving stellar mass and radius estimates: a new reference function for the Δν scaling relation

    NASA Astrophysics Data System (ADS)

    Guggenberger, Elisabeth; Hekker, Saskia; Basu, Sarbani; Bellinger, Earl

    2016-08-01

    The scaling relations between global asteroseismic observables and stellar properties are widely used to estimate masses and radii of stars exhibiting solar-like oscillations. Since the mass and radius of the Sun are known independently, the Sun is commonly used as a reference to scale to. However, the validity of the scaling relations depends on the homology between the star under study and the reference star. Solar-like oscillators span a wide range of masses and metallicities, as well as evolutionary phases. Most of these stars are therefore not homologous to the Sun. This leads to errors of up to 10 per cent (5 per cent) in mass (radius) when using the asteroseismic scaling relations with the Sun as the reference. In this paper, we derive a reference function to replace the solar-reference value used in the large-frequency separation scaling relation. Our function is the first that depends on both effective temperature and metallicity, and is applicable from the end of the main sequence to just above the bump on the red giant branch. This reference function improves the estimates of masses and radii determined through scaling relations by a factor of 2, i.e. allows masses and radii to be recovered with an accuracy of 5 per cent and 2 per cent, respectively.

  17. Significantly improving stellar mass and radius estimates: A new reference function for the Δν scaling relation

    NASA Astrophysics Data System (ADS)

    Guggenberger, Elisabeth; Hekker, Saskia; Basu, Sarbani; Bellinger, Earl

    2016-06-01

    The scaling relations between global asteroseismic observables and stellar properties are widely used to estimate masses and radii of stars exhibiting solar-like oscillations. Since the mass and radius of the Sun are known independently, the Sun is commonly used as a reference to scale to. However, the validity of the scaling relations depends on the homology between the star under study and the reference star. Solar-like oscillators span a wide range of masses and metallicities, as well as evolutionary phases. Most of these stars are therefore not homologous to the Sun. This leads to errors of up to 10% (5%) in mass (radius) when using the asteroseismic scaling relations with the Sun as the reference. In this paper we derive a reference function to replace the solar-reference value used in the large-frequency-separation scaling relation. Our function is the first that depends on both effective temperature and metallicity, and is applicable from the end of the main sequence to just above the bump on the red giant branch. This reference function improves the estimates of masses and radii determined through scaling relations by a factor of 2, i.e. allows masses and radii to be recovered with an accuracy of 5% and 2%, respectively.

  18. Estimates of Regional Equilibrium Line Altitudes and Net Mass Balance from MODIS Imagery

    NASA Astrophysics Data System (ADS)

    Shea, J. M.; Menounos, B.; Moore, R. D.

    2011-12-01

    Glacier mass balance is a key variable used to assess the health of glaciers and ice sheets. Estimates of glacier mass balance are required to model the dynamic response of glaciers and ice sheets to climate change, estimate sea-level contribution from surface melt, and document the response of glaciers to climate forcing. Annually resolved estimates of regional mass balance for mountain ranges is often inferred from a sparse network of ground-based measurements of mass balance for individual glaciers. Given that net mass balance is highly correlated with the annual equilibrium line altitude (ELA), we develop an automated approach to estimate the ELA, and by inference net mass balance, on large glaciers and icefields using MODIS 250 m imagery (MOD02QKM). We discriminate areas of bare ice and snow/firn using the product of MODIS' red (0.620 - 0.670 μ m) and near infrared (0.841 - 0.876 μ m) bands. To assess the skill in estimating glacier ELAs, we compare ELAs derived from (1) manual delineation and (2) unsupervised classification of the band product to ground-based observations of ELA and net mass balance at seven long term mass-balance monitoring sites in western North America (Gulkana, Wolverine, Lemon Creek, Taku, Place, Peyto, and South Cascade). Spatial and temporal variations in MODIS-derived ELAs provide an opportunity to validate regional mass-balance models, estimate surface melt contributions to sea-level rise, and examine the cryospheric response to climate change.

  19. Global surface mass time variations by using a two-step inversion for cumulating daily satellite gravity information

    NASA Astrophysics Data System (ADS)

    Ramillien, Guillaume; Frappart, Frappart; Seoane, Lucia

    2015-04-01

    We propose a new method to produce time series of global maps of surface mass variations by progressive integration of daily geopotential variations measured by orbiting satellites. In the case of the GRACE mission (2002 - 2012), these geopotential variations can be determined from very accurate inter-satellite K-Band Range Rate (KBRR) measurements of 5-second daily orbits. In particular, the along-track gravity contribution of hydrology is extracted by removing de-aliasing models for static field, atmosphere, oceans mass variations (including periodical tides), as well as polar movements. Our determination of surface mass sources consists of two successive dependent Kalman filter stages. The first one consists of reducing the satellite-based potential anomalies by adjusting the longest spatial wavelengths (i.e., low-degree spherical harmonics less than 5-6). In the second stage, the residual potential anomalies from the previous stage are used to recover surface mass density changes - in terms of Equivalent-Water Height (EWH) - over a global network of juxtaposed triangular elements. These surface tiles of ~40,000 km x km are imposed to be identical and homogeneously-distributed over the terrestrial sphere, however they can be adapted to the local geometry of the surface mass. Our global approach was tested by inverting simulated hydrology-related geopotential data, and successfully applied to estimate time-varying surface mass densities from real GRACE-based residuals. This strategy of combined Kalman filter-type inversions can also be useful for exploring the possibility of reaching better time and space resolutions for hydrology, that would be hopefully brought by future low altitude geodetic missions.

  20. EFFECTS OF BIASES IN VIRIAL MASS ESTIMATION ON COSMIC SYNCHRONIZATION OF QUASAR ACCRETION

    SciTech Connect

    Steinhardt, Charles L.

    2011-09-01

    Recent work using virial mass estimates and the quasar mass-luminosity plane has yielded several new puzzles regarding quasar accretion, including a sub-Eddington boundary (SEB) on most quasar accretion, near-independence of the accretion rate from properties of the host galaxy, and a cosmic synchronization of accretion among black holes of a common mass. We consider how these puzzles might change if virial mass estimation turns out to have a systematic bias. As examples, we consider two recent claims of mass-dependent biases in Mg II masses. Under any such correction, the surprising cosmic synchronization of quasar accretion rates and independence from the host galaxy remain. The slope and location of the SEB are very sensitive to biases in virial mass estimation, and various mass calibrations appear to favor different possible physical explanations for feedback between the central black hole and its environment. The alternative mass estimators considered do not simply remove puzzling quasar behavior, but rather replace it with new puzzles that may be more difficult to solve than those using current virial mass estimators and the Shen et al. catalog.

  1. The 2006 William Feinberg lecture: shifting the paradigm from stroke to global vascular risk estimation.

    PubMed

    Sacco, Ralph L

    2007-06-01

    By the year 2010, it is estimated that 18.1 million people worldwide will die annually because of cardiovascular diseases and stroke. "Global vascular risk" more broadly includes the multiple overlapping disease silos of stroke, myocardial infarction, peripheral arterial disease, and vascular death. Estimation of global vascular risk requires consideration of a variety of variables including demographics, environmental behaviors, and risk factors. Data from multiple studies suggest continuous linear relationships between the physiological vascular risk modulators of blood pressure, lipids, and blood glucose rather than treating these conditions as categorical risk factors. Constellations of risk factors may be more relevant than individual categorical components. Exciting work with novel risk factors may also have predictive value in estimates of global vascular risk. Advances in imaging have led to the measurement of subclinical conditions such as carotid intima-media thickness and subclinical brain conditions such as white matter hyperintensities and silent infarcts. These subclinical measurements may be intermediate stages in the transition from asymptomatic to symptomatic vascular events, appear to be associated with the fundamental vascular risk factors, and represent opportunities to more precisely quantitate disease progression. The expansion of studies in molecular epidemiology and detection of genetic markers underlying vascular risks also promises to extend our precision of global vascular risk estimation. Global vascular risk estimation will require quantitative methods that bundle these multi-dimensional data into more precise estimates of future risk. The power of genetic information coupled with data on demographics, risk-inducing behaviors, vascular risk modulators, biomarkers, and measures of subclinical conditions should provide the most realistic approximation of an individual's future global vascular risk. The ultimate public health benefit

  2. Assessing global dietary habits: a comparison of national estimates from the FAO and the Global Dietary Database1234

    PubMed Central

    Del Gobbo, Liana C; Khatibzadeh, Shahab; Imamura, Fumiaki; Micha, Renata; Shi, Peilin; Smith, Matthew; Myers, Samuel S; Mozaffarian, Dariush

    2015-01-01

    Background: Accurate data on dietary habits are crucial for understanding impacts on disease and informing policy priorities. Nation-specific food balance sheets from the United Nations FAO provided the only available global dietary estimates but with uncertain validity. Objectives: We investigated how FAO estimates compared with nationally representative, individual-based dietary surveys from the Global Dietary Database (GDD) and developed calibration equations to improve the validity of FAO data to estimate dietary intakes. Design: FAO estimates were matched to GDD data for 113 countries across the following 9 major dietary metrics for 30 y of data (1980–2009): fruit, vegetables, beans and legumes, nuts and seeds, whole grains, red and processed meats, fish and seafood, milk, and total energy. Both absolute and percentage differences in FAO and GDD mean estimates were evaluated. Linear regression was used to evaluate whether FAO estimates predicted GDD dietary intakes and whether this prediction varied according to age, sex, region, and time. Calibration equations were developed to adjust FAO estimates to approximate national dietary surveys validated by using randomly split data sets. Results: For most food groups, FAO estimates substantially overestimated individual-based dietary intakes by 74.5% (vegetables) and 270% (whole grains) while underestimating beans and legumes (−50%) and nuts and seeds (−29%) (P < 0.05 for each). In multivariate regressions, these overestimations and underestimations for each dietary factor further varied by age, sex, region, and time (P < 0.001 for each). Split–data set calibration models, which accounted for country-level covariates and other sources of heterogeneity, effectively adjusted FAO estimates to approximate estimates from national survey data (r = 0.47–0.80) with small SEs of prediction (generally 1–5 g/d). Conclusions: For all food groups and total energy, FAO estimates substantially exceeded or

  3. Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization

    NASA Astrophysics Data System (ADS)

    Kolby Smith, W.; Reed, Sasha C.; Cleveland, Cory C.; Ballantyne, Ashley P.; Anderegg, William R. L.; Wieder, William R.; Liu, Yi Y.; Running, Steven W.

    2016-03-01

    Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, `CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 +/- 1.50%) less than half of ESM-derived increases (7.6 +/- 1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data, we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle-climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.

  4. Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization

    USGS Publications Warehouse

    Smith, W. Kolby; Reed, Sasha C.; Cleveland, Cory C.; Ballantyne, Ashley P; Anderegg, William R. L.; Wieder, William R.; Liu, Yi Y; Running, Steven W.

    2015-01-01

    Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, ‘CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data, we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.

  5. Estimation of skeletal muscle mass from body creatine content

    NASA Technical Reports Server (NTRS)

    Pace, N.; Rahlmann, D. F.

    1982-01-01

    Procedures have been developed for studying the effect of changes in gravitational loading on skeletal muscle mass through measurements of the body creatine content. These procedures were developed for studies of gravitational scale effects in a four-species model, comprising the hamster, rat, guinea pig, and rabbit, which provides a sufficient range of body size for assessment of allometric parameters. Since intracellular muscle creatine concentration varies among species, and with age within a given species, the concentration values for metabolically mature individuals of these four species were established. The creatine content of the carcass, skin, viscera, smooth muscle, and skeletal muscle was determined for each species. In addition, the skeletal muscle mass of the major body components was determined, as well as the total and fat-free masses of the body and carcass, and the percent skeletal muscle in each. It is concluded that these procedures are particularly useful for studying the effect of gravitational loading on the skeletal muscle content of the animal carcass, which is the principal weight-bearing organ of the body.

  6. Bottom-up uncertainty estimates of global ammonia emissions from global agricultural production systems

    NASA Astrophysics Data System (ADS)

    Beusen, A. H. W.; Bouwman, A. F.; Heuberger, P. S. C.; Van Drecht, G.; Van Der Hoek, K. W.

    Here we present an uncertainty analysis of NH 3 emissions from agricultural production systems based on a global NH 3 emission inventory with a 5×5 min resolution. Of all results the mean is given with a range (10% and 90% percentile). The uncertainty range for the global NH 3 emission from agricultural systems is 27-38 (with a mean of 32) Tg NH 3-N yr -1, N fertilizer use contributing 10-12 (11) Tg yr -1 and livestock production 16-27 (21) Tg yr -1. Most of the emissions from livestock production come from animal houses and storage systems (31-55%); smaller contributions come from the spreading of animal manure (23-38%) and grazing animals (17-37%). This uncertainty analysis allows for identifying and improving those input parameters with a major influence on the results. The most important determinants of the uncertainty related to the global agricultural NH 3 emission comprise four parameters (N excretion rates, NH 3 emission rates for manure in animal houses and storage, the fraction of the time that ruminants graze and the fraction of non-agricultural use of manure) specific to mixed and landless systems, and total animal stocks. Nitrogen excretion rates and NH 3 emission rates from animal houses and storage systems are shown consistently to be the most important parameters in most parts of the world. Input parameters for pastoral systems are less relevant. However, there are clear differences between world regions and individual countries, reflecting the differences in livestock production systems.

  7. TRMM Science Highlights and 3-hr Quasi-global Precipitation Estimates

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Einaudi, Franco (Technical Monitor)

    2002-01-01

    The Tropical Rainfall Measuring Mission (TRMM) has completed more than four years in orbit. A summary of research highlights will be presented focusing on application of TRMM data to topics ranging over climate analysis, improving forecasts, precipitation processes and non-precipitation applications. One focus of the talk will be the quasi-global TRMM real-time merged rainfall analysis with 3-hr resolution, which uses TRMM to calibrate estimates from other polar-orbit and geosynchronous satellites. These rainfall estimates provide useful information for applications for assimilation into numerical models and for hydrological studies. The status of precipitation estimates from different TRMM instruments and algorithms will be described. Monthly surface rainfall estimates over the ocean based on different instruments on TRMM currently differ by 20% in overall mean. In addition, time changes in global ocean rainfall between El Nino and La Nina conditions show differences between the active and passive microwave products. Improved versions of algorithms will shortly resolve most of these differences. The TRMM rainfall estimates are intercompared among themselves and with other estimates, including those of the standard, monthly Global Precipitation Climatology Project (GPCP) analysis. A four-year TRMM rainfall climatology is presented, including anomaly fields related to the changing ENSO situation during the mission. The evolution of precipitation analysis incorporating Advanced Microwave Scanning Radiometer (AMSR) data on AQUA and ADEOS II and eventually data from the Global Precipitation Mission (GPM) will also be described.

  8. Estimating initial contaminant mass based on fitting mass-depletion functions to contaminant mass discharge data: Testing method efficacy with SVE operations data

    NASA Astrophysics Data System (ADS)

    Mainhagu, J.; Brusseau, M. L.

    2016-09-01

    The mass of contaminant present at a site, particularly in the source zones, is one of the key parameters for assessing the risk posed by contaminated sites, and for setting and evaluating remediation goals and objectives. This quantity is rarely known and is challenging to estimate accurately. This work investigated the efficacy of fitting mass-depletion functions to temporal contaminant mass discharge (CMD) data as a means of estimating initial mass. Two common mass-depletion functions, exponential and power functions, were applied to historic soil vapor extraction (SVE) CMD data collected from 11 contaminated sites for which the SVE operations are considered to be at or close to essentially complete mass removal. The functions were applied to the entire available data set for each site, as well as to the early-time data (the initial 1/3 of the data available). Additionally, a complete differential-time analysis was conducted. The latter two analyses were conducted to investigate the impact of limited data on method performance, given that the primary mode of application would be to use the method during the early stages of a remediation effort. The estimated initial masses were compared to the total masses removed for the SVE operations. The mass estimates obtained from application to the full data sets were reasonably similar to the measured masses removed for both functions (13 and 15% mean error). The use of the early-time data resulted in a minimally higher variation for the exponential function (17%) but a much higher error (51%) for the power function. These results suggest that the method can produce reasonable estimates of initial mass useful for planning and assessing remediation efforts.

  9. Estimating initial contaminant mass based on fitting mass-depletion functions to contaminant mass discharge data: Testing method efficacy with SVE operations data.

    PubMed

    Mainhagu, J; Brusseau, M L

    2016-09-01

    The mass of contaminant present at a site, particularly in the source zones, is one of the key parameters for assessing the risk posed by contaminated sites, and for setting and evaluating remediation goals and objectives. This quantity is rarely known and is challenging to estimate accurately. This work investigated the efficacy of fitting mass-depletion functions to temporal contaminant mass discharge (CMD) data as a means of estimating initial mass. Two common mass-depletion functions, exponential and power functions, were applied to historic soil vapor extraction (SVE) CMD data collected from 11 contaminated sites for which the SVE operations are considered to be at or close to essentially complete mass removal. The functions were applied to the entire available data set for each site, as well as to the early-time data (the initial 1/3 of the data available). Additionally, a complete differential-time analysis was conducted. The latter two analyses were conducted to investigate the impact of limited data on method performance, given that the primary mode of application would be to use the method during the early stages of a remediation effort. The estimated initial masses were compared to the total masses removed for the SVE operations. The mass estimates obtained from application to the full data sets were reasonably similar to the measured masses removed for both functions (13 and 15% mean error). The use of the early-time data resulted in a minimally higher variation for the exponential function (17%) but a much higher error (51%) for the power function. These results suggest that the method can produce reasonable estimates of initial mass useful for planning and assessing remediation efforts. PMID:27494132

  10. Glaciers. Attribution of global glacier mass loss to anthropogenic and natural causes.

    PubMed

    Marzeion, Ben; Cogley, J Graham; Richter, Kristin; Parkes, David

    2014-08-22

    The ongoing global glacier retreat is affecting human societies by causing sea-level rise, changing seasonal water availability, and increasing geohazards. Melting glaciers are an icon of anthropogenic climate change. However, glacier response times are typically decades or longer, which implies that the present-day glacier retreat is a mixed response to past and current natural climate variability and current anthropogenic forcing. Here we show that only 25 ± 35% of the global glacier mass loss during the period from 1851 to 2010 is attributable to anthropogenic causes. Nevertheless, the anthropogenic signal is detectable with high confidence in glacier mass balance observations during 1991 to 2010, and the anthropogenic fraction of global glacier mass loss during that period has increased to 69 ± 24%. PMID:25123485

  11. Dark Matter and neutrino masses from global U(1) B - L symmetry breaking

    NASA Astrophysics Data System (ADS)

    Lindner, Manfred; Schmidt, Daniel; Schwetz, Thomas

    2011-11-01

    We present a scenario where neutrino masses and Dark Matter are related due to a global U(1) B - L symmetry. Specifically we consider neutrino mass generation via the Zee-Babu two-loop mechanism, augmented by a scalar singlet whose VEV breaks the global U(1) B - L symmetry. In order to obtain a Dark Matter candidate we introduce two Standard Model singlet fermions. They form a Dirac particle and are stable because of a remnant Z2 symmetry. Hence, in this model the stability of Dark Matter follows from the global U(1) B - L symmetry. We discuss the Dark Matter phenomenology of the model, and compare it to similar models based on gauged U(1) B - L. We argue that in contrast to the gauged versions, the model based on the global symmetry does not suffer from severe constraints from Z‧ searches.

  12. Towards an estimation of water masses formation areas from SMOS-based TS diagrams

    NASA Astrophysics Data System (ADS)

    Klockmann, Marlene; Sabia, Roberto; Fernandez-Prieto, Diego; Donlon, Craig; Font, Jordi

    2014-05-01

    Temperature-Salinity (TS) diagrams emphasize the mutual variability of ocean temperature and salinity values, relating them to the corresponding density. Canonically used in oceanography, they provide a means to characterize and trace ocean water masses. In [1], a first attempt to estimate surface-layer TS diagrams based on satellite measurements has been performed, profiting from the recent availability of spaceborne salinity data. In fact, the Soil Moisture and Ocean Salinity (SMOS, [2]) and the Aquarius/SAC-D [3] satellite missions allow to study the dynamical patterns of Sea Surface Salinity (SSS) for the first time on a global scale. In [4], given SMOS and Aquarius salinity estimates, and by also using Sea Surface Temperature (SST) from the Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA, [5]) effort, experimental satellite-based TS diagrams have been routinely derived for the year 2011. They have been compared with those computed from ARGO-buoys interpolated fields, referring to a customised partition of the global ocean into seven regions, according to the water masses classification of [6]. In [7], moreover, besides using TS diagrams as a diagnostic tool to evaluate the temporal variation of SST and SSS (and their corresponding density) as estimated by satellite measurements, the emphasis was on the interpretation of the geographical deviations with respect to the ARGO baseline (aiming at distinguishing between the SSS retrieval errors and the additional information contained in the satellite data with respect to ARGO). In order to relate these mismatches to identifiable oceanographic structures and processes, additional satellite datasets of ocean currents, evaporation/precipitation fluxes, and wind speed have been super-imposed. Currently, the main focus of the study deals with the exploitation of these TS diagrams as a prognostic tool to derive water masses formation areas. Firstly, following the approach described in [8], the surface

  13. Specific Mass Estimates for A Vapor Core Reactor With MHD

    SciTech Connect

    Knight, Travis; Smith, Blair; Anghaie, Samim

    2002-07-01

    This study investigated the development of a system concept for space power generation and nuclear electric propulsion based on a vapor core reactor (VCR) with magnetohydrodynamic (MHD) power conversion system, coupled to a magnetoplasma-dynamic (MPD) thruster. The VCR is a liquid-vapor core reactor concept operating with metallic uranium or uranium tetrafluoride (UF{sub 4}) vapor as the fissioning fuel and alkali metals or their fluorides as working fluid in a closed Rankine cycle with MHD energy conversion. Gaseous and liquid-vapor core reactors can potentially provide the highest reactor and cycle temperature among all existing or proposed fission reactor designs. This unique feature makes this reactor concept a very natural and attractive candidate for very high power (10 to 1000 MWe) and low specific mass (0.4 to 5 kg/kWe) nuclear electric propulsion (NEP) applications since the MHD output could be coupled with minimal power conditioning to MPD thrusters or other types of thruster for producing thrust at very high specific impulse (I{sub sp} 1500 to 10,000 s). The exceptional specific mass performance of an optimized VCRMHD- NEP system could lead to a dramatic reduction in the cost and duration of manned or robotic interplanetary as well as interstellar missions. The VCR-MHD-NEP system could enable very efficient Mars cargo transfers or short (<8 month) Mars round trips with less initial mass in low Earth orbit (IMLEO). The system could also enable highly efficient lunar cargo transfer and rapid missions to other destinations throughout the solar system. (authors)

  14. MASS STORAGE ESTIMATES FOR THE DIGITAL MAPPING AREA.

    USGS Publications Warehouse

    Light, Donald L.

    1983-01-01

    Modern computer technology offers cartographers the potential for transition from conventional film-oriented methods to digital techniques as the way of mapping in the future. Traditional methods utilizing silver halide aerial and lithographic films for storage are time proven, and film is a very high density archival storage media. In view of this, proponents of the digital era recognize that a breakthrough in mass storage technology may be required to attain a reasonable degree of computerization of the cartographic mapping and data management process.

  15. A New Equation to Estimate Muscle Mass from Creatinine and Cystatin C

    PubMed Central

    Kim, Cheol-Ho; Kim, Kwang-il; Chin, Ho Jun; Lee, Hajeong

    2016-01-01

    Background With evaluation for physical performance, measuring muscle mass is an important step in detecting sarcopenia. However, there are no methods to estimate muscle mass from blood sampling. Methods To develop a new equation to estimate total-body muscle mass with serum creatinine and cystatin C level, we designed a cross-sectional study with separate derivation and validation cohorts. Total body muscle mass and fat mass were measured using dual-energy x-ray absorptiometry (DXA) in 214 adults aged 25 to 84 years who underwent physical checkups from 2010 to 2013 in a single tertiary hospital. Serum creatinine and cystatin C levels were also examined. Results Serum creatinine was correlated with muscle mass (P < .001), and serum cystatin C was correlated with body fat mass (P < .001) after adjusting glomerular filtration rate (GFR). After eliminating GFR, an equation to estimate total-body muscle mass was generated and coefficients were calculated in the derivation cohort. There was an agreement between muscle mass calculated by the novel equation and measured by DXA in both the derivation and validation cohort (P < .001, adjusted R2 = 0.829, β = 0.95, P < .001, adjusted R2 = 0.856, β = 1.03, respectively). Conclusion The new equation based on serum creatinine and cystatin C levels can be used to estimate total-body muscle mass. PMID:26849842

  16. Estimating nutrient loadings using chemical mass balance approach.

    PubMed

    Jain, C K; Singhal, D C; Sharma, M K

    2007-11-01

    The river Hindon is one of the important tributaries of river Yamuna in western Uttar Pradesh (India) and carries pollution loads from various municipal and industrial units and surrounding agricultural areas. The main sources of pollution in the river include municipal wastes from Saharanpur, Muzaffarnagar and Ghaziabad urban areas and industrial effluents of sugar, pulp and paper, distilleries and other miscellaneous industries through tributaries as well as direct inputs. In this paper, chemical mass balance approach has been used to assess the contribution from non-point sources of pollution to the river. The river system has been divided into three stretches depending on the land use pattern. The contribution of point sources in the upper and lower stretches are 95 and 81% respectively of the total flow of the river while there is no point source input in the middle stretch. Mass balance calculations indicate that contribution of nitrate and phosphate from non-point sources amounts to 15.5 and 6.9% in the upper stretch and 13.1 and 16.6% in the lower stretch respectively. Observed differences in the load along the river may be attributed to uncharacterized sources of pollution due to agricultural activities, remobilization from or entrainment of contaminated bottom sediments, ground water contribution or a combination of these sources. PMID:17616829

  17. Estimation of the mass outflow rates around rotating black holes

    NASA Astrophysics Data System (ADS)

    Aktar, Ramiz; Das, Santabrata

    We consider steady, advective, rotating, inviscid accretion disc around the spinning black holes to compute the mass outflow rate (R_{dot{m}}) defined as the ratio of mass flux of outflowing to the inflowing matter. Due to centrifugal barrier, accreting matter suffers discontinuous shock transition and because of shock compression, the post-shock matter becomes hot and denser than the pre-shock matter. We call the post-shock disc as Post Shock Corona (PSC). During accretion, a part of the inflowing matter deflects as bipolar outflows due to the presence of excess thermal gradient force at PSC. We find that R_{dot{m}}is directly correlated with the spin of the black hole (a_{k}) for the same set of inflow parameter, namely specific energy (E) and specific angular momentum (λ). We observe that the maximum outflow rate(R_{dot{m}}^{max}) weakly depends on spin (a_{k}) that lies in the range˜ 17% - 18% of the inflow rate.

  18. The Effect of Mergers on Galaxy Cluster Mass Estimates

    NASA Astrophysics Data System (ADS)

    Johnson, Ryan E.; Zuhone, John A.; Thorsen, Tessa; Hinds, Andre

    2015-08-01

    At vertices within the filamentary structure that describes the universal matter distribution, clusters of galaxies grow hierarchically through merging with other clusters. As such, the most massive galaxy clusters should have experienced many such mergers in their histories. Though we cannot see them evolve over time, these mergers leave lasting, measurable effects in the cluster galaxies' phase space. By simulating several different galaxy cluster mergers here, we examine how the cluster galaxies kinematics are altered as a result of these mergers. Further, we also examine the effect of our line of sight viewing angle with respect to the merger axis. In projecting the 6-dimensional galaxy phase space onto a 3-dimensional plane, we are able to simulate how these clusters might actually appear to optical redshift surveys. We find that for those optical cluster statistics which are most often used as a proxy for the cluster mass (variants of σv), the uncertainty due to an inprecise or unknown line of sight may alter the derived cluster masses moreso than the kinematic disturbance of the merger itself. Finally, by examining these, and several other clustering statistics, we find that significant events (such as pericentric crossings) are identifiable over a range of merger initial conditions and from many different lines of sight.

  19. A global review of species-specific shark-fin-to-body-mass ratios and relevant legislation.

    PubMed

    Biery, L; Pauly, D

    2012-04-01

    In this review, shark-fin-to-body-mass ratios, which have been legislated by several countries as a means of regulating and monitoring shark fisheries, have been compiled and reviewed. Observed and legislated wet-fin-mass-to-round-mass (M(fw) :M(r) ) ratios have been collected for 50 species and eight countries. Wet to dry-fin mass conversion factors have also been reviewed. Existing shark fishery legislation was compiled by political entity and regional fishery management organizations (RFMO). The mean observed M(fw) :M(r) ratio for all species was 3·0%, but actual fin to body-mass ratios varied considerably by species and location. Species-specific mean ratios ranged from 1·1 to 10·9%, and estimated mean ratios ranged from 1·5 to 6·1% by country, depending on fin-cutting practices and the mix of exploited species. The mean conversion factor for wet to dry-fin mass was 0·43. Shark-related legislation was found to exist in 37 countries and the 22 maritime members of the European Union, and shark-related regulations have been designated by nine RFMOs. Results suggest that currently regulated ratios may not be appropriate for all species and fin-cutting practices, and regulations based on generalized ratios for all sharks may be inadequate. Alternative policies may be necessary for the effective management of global shark fisheries. PMID:22497402

  20. The Effect of Antarctic Ice Mass Changes on Crustal Motion and Global Geodetic Observables

    NASA Technical Reports Server (NTRS)

    James, T. S.; Ivins, E. R.

    1995-01-01

    Glaciological estimates of the present-day ice mass balance of Antarctica vary widely, indicating the need for additional data to constrain mass-balance models. For example, recent studies find both a positive and a negative mass balance of the Antarctic ice sheet. Analysis of studies suggest that observations of present-day crustal motion, as obtained from a GPS survey could assist in defining models.

  1. How does mass loading impact local versus global control on dayside reconnection?

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Brambles, O. J.; Wiltberger, M.; Lotko, W.; Ouellette, J. E.; Lyon, J. G.

    2016-03-01

    This paper investigates the effects of magnetospheric mass loading on the control of dayside magnetic reconnection using global magnetospheric simulations. The study iys motivated by a recent debate on whether the integrated dayside magnetic reconnection rate is solely controlled by local processes (local-control theory) or global merging processes (global-control theory). The local-control theory suggests that the integrated dayside reconnection rate is controlled by the local plasma parameters. The global-control theory argues that the integrated rate is determined by the net force acting on the flow in the magnetosheath rather than the local microphysics. Controlled numerical simulations using idealized ionospheric outflow specifications suggest a possible mixed-control theory, that is, (1) a small amount of mass loading at the dayside magnetopause only redistributes local reconnection rate without a significant change in the integrated reconnection rate and (2) a large amount of mass loading reduces both local reconnection rates and the integrated reconnection rate on the dayside. The transition between global-control- and local-control-dominated regimes depends on (but not limited to) the source region, the amount, the location, and the spatial extension of the mass loading at the dayside magnetopause.

  2. Volcanism, Impacts and Mass Extinctions: A case study of the Deccan Traps and its global effects

    NASA Astrophysics Data System (ADS)

    Keller, G.

    2012-12-01

    The nature and causes of mass extinctions in the geological past have remained topics of intense scientific debate for the past three decades. Central to this debate is the question of whether one, or several large bolide impacts, the eruption of large igneous provinces (LIP) or a combination of the two were the primary mechanisms driving the environmental changes that are universally regarded as the proximate causes for four of the five major Phanerozoic extinction events. Recent years have seen a revolution in our understanding of interplanetary environments, LIP eruptions and their environmental effects such that the simple impact-kill scenario no longer seems an adequate explanation for the Cretaceous-Tertiary boundary (KTB) or any other mass extinction. The KTB is the only mass extinction associated with both impact (Chixculub) and flood basalts (Deccan Traps) and therefore an excellent case study to evaluate the potential causes and effects. Deccan eruptions likely occurred as "pulses", with some gigantic megaflows 1500 km across India and with estimated volumes >10,000 km3 that may have erupted over very short time intervals. For comparison, the largest historical basalt eruption in 1783 in Iceland (Laki) ejected some 15 km3 of lava in about a year. A single Deccan megaflow would have been equivalent to 667 Laki. The vast amount of carbon and sulphur dioxides injected into the atmosphere from just one Deccan megaflow would have been on the same order of magnitude as those estimated for the Chicxulub impact. Deccan Traps erupted in three main phases with 6% total Deccan volume in phase-1 (base C30n), 80% in phase-2 (C29r) and 14% in phase-3 (C29n). Phase-2 and phase-3 each produced four giant megaflows leading to the KTB mass extinction and the long delayed biotic recovery, respectively. Data from infra- and intertrappean sediments of these megaflows drilled in the Krishna-Godavari Basin by India's Oil and Natural Gas Corporation reveal swift and devastating

  3. Global and Regional Estimates of Prevalent and Incident Herpes Simplex Virus Type 1 Infections in 2012

    PubMed Central

    Looker, Katharine J.; Magaret, Amalia S.; May, Margaret T.; Turner, Katherine M. E.; Vickerman, Peter; Gottlieb, Sami L.; Newman, Lori M.

    2015-01-01

    Background Herpes simplex virus type 1 (HSV-1) commonly causes orolabial ulcers, while HSV-2 commonly causes genital ulcers. However, HSV-1 is an increasing cause of genital infection. Previously, the World Health Organization estimated the global burden of HSV-2 for 2003 and for 2012. The global burden of HSV-1 has not been estimated. Methods We fitted a constant-incidence model to pooled HSV-1 prevalence data from literature searches for 6 World Health Organization regions and used 2012 population data to derive global numbers of 0-49-year-olds with prevalent and incident HSV-1 infection. To estimate genital HSV-1, we applied values for the proportion of incident infections that are genital. Findings We estimated that 3709 million people (range: 3440–3878 million) aged 0–49 years had prevalent HSV-1 infection in 2012 (67%), with highest prevalence in Africa, South-East Asia and Western Pacific. Assuming 50% of incident infections among 15-49-year-olds are genital, an estimated 140 million (range: 67–212 million) people had prevalent genital HSV-1 infection, most of which occurred in the Americas, Europe and Western Pacific. Conclusions The global burden of HSV-1 infection is huge. Genital HSV-1 burden can be substantial but varies widely by region. Future control efforts, including development of HSV vaccines, should consider the epidemiology of HSV-1 in addition to HSV-2, and especially the relative contribution of HSV-1 to genital infection. PMID:26510007

  4. Active galactic nucleus black hole mass estimates in the era of time domain astronomy

    SciTech Connect

    Kelly, Brandon C.; Treu, Tommaso; Pancoast, Anna; Malkan, Matthew; Woo, Jong-Hak

    2013-12-20

    We investigate the dependence of the normalization of the high-frequency part of the X-ray and optical power spectral densities (PSDs) on black hole mass for a sample of 39 active galactic nuclei (AGNs) with black hole masses estimated from reverberation mapping or dynamical modeling. We obtained new Swift observations of PG 1426+015, which has the largest estimated black hole mass of the AGNs in our sample. We develop a novel statistical method to estimate the PSD from a light curve of photon counts with arbitrary sampling, eliminating the need to bin a light curve to achieve Gaussian statistics, and we use this technique to estimate the X-ray variability parameters for the faint AGNs in our sample. We find that the normalization of the high-frequency X-ray PSD is inversely proportional to black hole mass. We discuss how to use this scaling relationship to obtain black hole mass estimates from the short timescale X-ray variability amplitude with precision ∼0.38 dex. The amplitude of optical variability on timescales of days is also anticorrelated with black hole mass, but with larger scatter. Instead, the optical variability amplitude exhibits the strongest anticorrelation with luminosity. We conclude with a discussion of the implications of our results for estimating black hole mass from the amplitude of AGN variability.

  5. A strategy for merging objective estimates of global daily precipitation from gauge observations, satellite estimates, and numerical predictions

    NASA Astrophysics Data System (ADS)

    Nie, Suping; Wu, Tongwen; Luo, Yong; Deng, Xueliang; Shi, Xueli; Wang, Zaizhi; Liu, Xiangwen; Huang, Jianbin

    2016-07-01

    This paper describes a strategy for merging daily precipitation information from gauge observations, satellite estimates (SEs), and numerical predictions at the global scale. The strategy is designed to remove systemic bias and random error from each individual daily precipitation source to produce a better gridded global daily precipitation product through three steps. First, a cumulative distribution function matching procedure is performed to remove systemic bias over gauge-located land areas. Then, the overall biases in SEs and model predictions (MPs) over ocean areas are corrected using a rescaled strategy based on monthly precipitation. Third, an optimal interpolation (OI)-based merging scheme (referred as the HL-OI scheme) is used to combine unbiased gauge observations, SEs, and MPs to reduce random error from each source and to produce a gauge—satellite-model merged daily precipitation analysis, called BMEP-d (Beijing Climate Center Merged Estimation of Precipitation with daily resolution), with complete global coverage. The BMEP-d data from a four-year period (2011-14) demonstrate the ability of the merging strategy to provide global daily precipitation of substantially improved quality. Benefiting from the advantages of the HL-OI scheme for quantitative error estimates, the better source data can obtain more weights during the merging processes. The BMEP-d data exhibit higher consistency with satellite and gauge source data at middle and low latitudes, and with model source data at high latitudes. Overall, independent validations against GPCP-1DD (GPCP one-degree daily) show that the consistencies between BMEP-d and GPCP-1DD are higher than those of each source dataset in terms of spatial pattern, temporal variability, probability distribution, and statistical precipitation events.

  6. Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans

    PubMed Central

    Walker, Ann C.; O'Connor-Semmes, Robin L.; Leonard, Michael S.; Miller, Ram R.; Stimpson, Stephen A.; Turner, Scott M.; Ravussin, Eric; Cefalu, William T.; Hellerstein, Marc K.; Evans, William J.

    2014-01-01

    Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19–30 yr, 70–84 yr), 15 postmenopausal women (51–62 yr, 70–84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA. PMID:24764133

  7. Global well-posedness for the mass-critical nonlinear Schrödinger equation on T

    NASA Astrophysics Data System (ADS)

    Li, Yongsheng; Wu, Yifei; Xu, Guixiang

    2011-03-01

    We consider the global well-posedness for the Cauchy problem of the mass-critical nonlinear Schrödinger equations in the periodic case. We show that it is globally well-posed in H(T) for any s>2/5. This improves the related work of Bourgain (2004) [2]. The key point is that we combine I-method with the resonant decomposition, which is developed in Colliander et al. (2008) [9], Li et al. (2011) [15], Miao et al. (2010) [16]. Another new ingredient here is that we obtain a bilinear Strichartz estimates in the periodic case which improves slightly the result given in De Silva et al. (2007) [11].

  8. Global and regional estimates of cancer mortality and incidence by site: II. results for the global burden of disease 2000

    PubMed Central

    Shibuya, Kenji; Mathers, Colin D; Boschi-Pinto, Cynthia; Lopez, Alan D; Murray, Christopher JL

    2002-01-01

    Background Mortality estimates alone are not sufficient to understand the true magnitude of cancer burden. We present the detailed estimates of mortality and incidence by site as the basis for the future estimation of cancer burden for the Global Burden of Disease 2000 study. Methods Age- and sex- specific mortality envelope for all malignancies by region was derived from the analysis of country life-tables and cause of death. We estimated the site-specific cancer mortality distributions from vital records and cancer survival model. The regional cancer mortality by site is estimated by disaggregating the regional cancer mortality envelope based on the mortality distribution. Estimated incidence-to-mortality rate ratios were used to back calculate the final cancer incidence estimates by site. Results In 2000, cancer accounted for over 7 million deaths (13% of total mortality) and there were more than 10 million new cancer cases world wide in 2000. More than 60% of cancer deaths and approximately half of new cases occurred in developing regions. Lung cancer was the most common cancers in the world, followed by cancers of stomach, liver, colon and rectum, and breast. There was a significant variations in the distribution of site-specific cancer mortality and incidence by region. Conclusions Despite a regional variation, the most common cancers are potentially preventable. Cancer burden estimation by taking into account both mortality and morbidity is an essential step to set research priorities and policy formulation. Also it can used for setting priorities when combined with data on costs of interventions against cancers. PMID:12502432

  9. The estimation of body mass index and physical attractiveness is dependent on the observer's own body mass index.

    PubMed

    Tovée, M J; Emery, J L; Cohen-Tovée, E M

    2000-10-01

    A disturbance in the evaluation of personal body mass and shape is a key feature of both anorexia and bulimia nervosa. However, it is uncertain whether overestimation is a causal factor in the development of these eating disorders or is merely a secondary effect of having a low body mass. Moreover, does this overestimation extend to the perception of other people's bodies? Since body mass is an important factor in the perception of physical attractiveness, we wanted to determine whether this putative overestimation of self body mass extended to include the perceived attractiveness of others. We asked 204 female observers (31 anorexic, 30 bulimic and 143 control) to estimate the body mass and rate the attractiveness of a set of 25 photographic images showing people of varying body mass index (BMI). BMI is a measure of weight scaled for height (kg m(- 2)). The observers also estimated their own BMI. Anorexic and bulimic observers systematically overestimated the body mass of both their own and other people's bodies, relative to controls, and they rated a significantly lower body mass to be optimally attractive. When the degree of overestimation is plotted against the BMI of the observer there is a strong correlation. Taken across all our observers, as the BMI of the observer declines, the overestimation of body mass increases. One possible explanation for this result is that the overestimation is a secondary effect caused by weight loss. Moreover, if the degree of body mass overestimation is taken into account, then there are no significant differences in the perceptions of attractiveness between anorexic and bulimic observers and control observers. Our results suggest a significant perceptual overestimation of BMI that is based on the observer's own BMI and not correlated with cognitive factors, and suggests that this overestimation in eating-disordered patients must be addressed directly in treatment regimes. PMID:11075712

  10. The estimation of body mass index and physical attractiveness is dependent on the observer's own body mass index.

    PubMed Central

    Tovée, M J; Emery, J L; Cohen-Tovée, E M

    2000-01-01

    A disturbance in the evaluation of personal body mass and shape is a key feature of both anorexia and bulimia nervosa. However, it is uncertain whether overestimation is a causal factor in the development of these eating disorders or is merely a secondary effect of having a low body mass. Moreover, does this overestimation extend to the perception of other people's bodies? Since body mass is an important factor in the perception of physical attractiveness, we wanted to determine whether this putative overestimation of self body mass extended to include the perceived attractiveness of others. We asked 204 female observers (31 anorexic, 30 bulimic and 143 control) to estimate the body mass and rate the attractiveness of a set of 25 photographic images showing people of varying body mass index (BMI). BMI is a measure of weight scaled for height (kg m(- 2)). The observers also estimated their own BMI. Anorexic and bulimic observers systematically overestimated the body mass of both their own and other people's bodies, relative to controls, and they rated a significantly lower body mass to be optimally attractive. When the degree of overestimation is plotted against the BMI of the observer there is a strong correlation. Taken across all our observers, as the BMI of the observer declines, the overestimation of body mass increases. One possible explanation for this result is that the overestimation is a secondary effect caused by weight loss. Moreover, if the degree of body mass overestimation is taken into account, then there are no significant differences in the perceptions of attractiveness between anorexic and bulimic observers and control observers. Our results suggest a significant perceptual overestimation of BMI that is based on the observer's own BMI and not correlated with cognitive factors, and suggests that this overestimation in eating-disordered patients must be addressed directly in treatment regimes. PMID:11075712

  11. Global Burden of Leptospirosis: Estimated in Terms of Disability Adjusted Life Years

    PubMed Central

    Torgerson, Paul R.; Hagan, José E.; Costa, Federico; Calcagno, Juan; Kane, Michael; Martinez-Silveira, Martha S.; Goris, Marga G. A.; Stein, Claudia; Ko, Albert I.; Abela-Ridder, Bernadette

    2015-01-01

    Background Leptospirosis, a spirochaetal zoonosis, occurs in diverse epidemiological settings and affects vulnerable populations, such as rural subsistence farmers and urban slum dwellers. Although leptospirosis can cause life-threatening disease, there is no global burden of disease estimate in terms of Disability Adjusted Life Years (DALYs) available. Methodology/Principal Findings We utilised the results of a parallel publication that reported global estimates of morbidity and mortality due to leptospirosis. We estimated Years of Life Lost (YLLs) from age and gender stratified mortality rates. Years of Life with Disability (YLDs) were developed from a simple disease model indicating likely sequelae. DALYs were estimated from the sum of YLLs and YLDs. The study suggested that globally approximately 2·90 million DALYs are lost per annum (UIs 1·25–4·54 million) from the approximately annual 1·03 million cases reported previously. Males are predominantly affected with an estimated 2·33 million DALYs (UIs 0·98–3·69) or approximately 80% of the total burden. For comparison, this is over 70% of the global burden of cholera estimated by GBD 2010. Tropical regions of South and South-east Asia, Western Pacific, Central and South America, and Africa had the highest estimated leptospirosis disease burden. Conclusions/Significance Leptospirosis imparts a significant health burden worldwide, which approach or exceed those encountered for a number of other zoonotic and neglected tropical diseases. The study findings indicate that highest burden estimates occur in resource-poor tropical countries, which include regions of Africa where the burden of leptospirosis has been under-appreciated and possibly misallocated to other febrile illnesses such as malaria. PMID:26431366

  12. Estimation of the mass center and dynamics of a spherical test mass for gravitational reference sensors

    NASA Astrophysics Data System (ADS)

    Conklin, John W.

    Exciting new fields of physics and precision inertial navigation can be realized by reducing test mass disturbances in drag-free spacecraft orders of magnitude below what has currently been demonstrated. The mass center of an ideal drag-free test mass is a reference point traveling along a pure geodesic. The purpose of the drag-free spacecraft is to shield the test mass from all external disturbances, and at the same time, not to introduce additional disturbances. A sphere has the advantage of invariance of orientation. A spherical test mass, therefore, requires no forcing on the part of the spacecraft to control the test mass orientation. With the need for actuation eliminated, the gap between the test mass and spacecraft can be opened up to sizes on the order of the sphere's radius. Elimination of test mass forcing and a large gap reduces, or all together eliminates, the largest disturbances acting on the test mass. Furthermore, spinning the sphere can spectrally shift body-fixed features to frequencies that do-not interfere with the drag-free control or the science mission. The angular momentum vector of the spinning sphere is a quantity that is robust against residual torques providing an orientation reference for the local inertial frame. In this dissertation a generic model for the output of a drag-free sensor with a spinning spherical test mass is developed. A measurable feature of the test mass (surface geometry with respect to the mass center, magnetic potential, etc.) is written as an expansion in spherical harmonics. The rigid body motion of the test mass relative to the sensor is assumed to obey Euler's equations on short time scales, with angular momentum decay and polhode damping due to residual disturbances modeled on longer time scales, greater than say one clay. The validity of this model is demonstrated to approximately 1% using the Gravity Probe B flight data spanning 1 year. The success of this model allows for the prediction of polhode

  13. Importance of representing optical depth variability for estimates of global line-shaped contrail radiative forcing

    PubMed Central

    Kärcher, Bernd; Burkhardt, Ulrike; Ponater, Michael; Frömming, Christine

    2010-01-01

    Estimates of the global radiative forcing by line-shaped contrails differ mainly due to the large uncertainty in contrail optical depth. Most contrails are optically thin so that their radiative forcing is roughly proportional to their optical depth and increases with contrail coverage. In recent assessments, the best estimate of mean contrail radiative forcing was significantly reduced, because global climate model simulations pointed at lower optical depth values than earlier studies. We revise these estimates by comparing the probability distribution of contrail optical depth diagnosed with a climate model with the distribution derived from a microphysical, cloud-scale model constrained by satellite observations over the United States. By assuming that the optical depth distribution from the cloud model is more realistic than that from the climate model, and by taking the difference between the observed and simulated optical depth over the United States as globally representative, we quantify uncertainties in the climate model’s diagnostic contrail parameterization. Revising the climate model results accordingly increases the global mean radiative forcing estimate for line-shaped contrails by a factor of 3.3, from 3.5 mW/m2 to 11.6 mW/m2 for the year 1992. Furthermore, the satellite observations and the cloud model point at higher global mean optical depth of detectable contrails than often assumed in radiative transfer (off-line) studies. Therefore, we correct estimates of contrail radiative forcing from off-line studies as well. We suggest that the global net radiative forcing of line-shaped persistent contrails is in the range 8–20 mW/m2 for the air traffic in the year 2000. PMID:20974909

  14. Importance of representing optical depth variability for estimates of global line-shaped contrail radiative forcing.

    PubMed

    Kärcher, Bernd; Burkhardt, Ulrike; Ponater, Michael; Frömming, Christine

    2010-11-01

    Estimates of the global radiative forcing by line-shaped contrails differ mainly due to the large uncertainty in contrail optical depth. Most contrails are optically thin so that their radiative forcing is roughly proportional to their optical depth and increases with contrail coverage. In recent assessments, the best estimate of mean contrail radiative forcing was significantly reduced, because global climate model simulations pointed at lower optical depth values than earlier studies. We revise these estimates by comparing the probability distribution of contrail optical depth diagnosed with a climate model with the distribution derived from a microphysical, cloud-scale model constrained by satellite observations over the United States. By assuming that the optical depth distribution from the cloud model is more realistic than that from the climate model, and by taking the difference between the observed and simulated optical depth over the United States as globally representative, we quantify uncertainties in the climate model's diagnostic contrail parameterization. Revising the climate model results accordingly increases the global mean radiative forcing estimate for line-shaped contrails by a factor of 3.3, from 3.5 mW/m(2) to 11.6 mW/m(2) for the year 1992. Furthermore, the satellite observations and the cloud model point at higher global mean optical depth of detectable contrails than often assumed in radiative transfer (off-line) studies. Therefore, we correct estimates of contrail radiative forcing from off-line studies as well. We suggest that the global net radiative forcing of line-shaped persistent contrails is in the range 8-20 mW/m(2) for the air traffic in the year 2000. PMID:20974909

  15. A GIS TECHNIQUE FOR ESTIMATING NATURAL ATTENUATION RATES AND MASS BALANCES

    EPA Science Inventory

    ABSTRACT: Regulatory approval of monitored natural attenuation (MNA) as a component for site remediation often requires a demonstration that contaminant mass has decreased significantly over time. Successful approval of MNA also typically requires an estimate of past and future n...

  16. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    SciTech Connect

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  17. A GIS TECHNIQUE FOR ESTIMATING NATURAL ATTENUATION RATES AND MASS BALANCES: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-ADA-01308 Durant, ND, Srinivasan, P, Faust, CR, Burnell, DK, Klein, KL, and Burden*, D.S. A GIS Technique for Estimating Natural Attenuation Rates and Mass Balances. Battelle's Sixth International ...

  18. Estimation of body mass index from the metrics of the first metatarsal

    NASA Astrophysics Data System (ADS)

    Dunn, Tyler E.

    Estimation of the biological profile from as many skeletal elements as possible is a necessity in both forensic and bioarchaeological contexts; this includes non-standard aspects of the biological profile, such as body mass index (BMI). BMI is a measure that allows for understanding of the composition of an individual and is traditionally divided into four groups: underweight, normal weight, overweight, and obese. BMI estimation incorporates both estimation of stature and body mass. The estimation of stature from skeletal elements is commonly included into the standard biological profile but the estimation of body mass needs to be further statistically validated to be consistently included. The bones of the foot, specifically the first metatarsal, may have the ability to estimate BMI given an allometric relationship to stature and the mechanical relationship to body mass. There are two commonly used methods for stature estimation, the anatomical method and the regression method. The anatomical method takes into account all of the skeletal elements that contribute to stature while the regression method relies on the allometric relationship between a skeletal element and living stature. A correlation between the metrics of the first metatarsal and living stature has been observed, and proposed as a method for valid stature estimation from the boney foot (Byers et al., 1989). Body mass estimation from skeletal elements relies on two theoretical frameworks: the morphometric and the mechanical approaches. The morphometric approach relies on the size relationship of the individual to body mass; the basic relationship between volume, density, and weight allows for body mass estimation. The body is thought of as a cylinder, and in order to understand the volume of this cylinder the diameter is needed. A commonly used proxy for this in the human body is skeletal bi-iliac breadth from rearticulated pelvic girdle. The mechanical method of body mass estimation relies on the

  19. A TRMM-Based System for Real-Time Quasi-Global Merged Precipitation Estimates

    NASA Technical Reports Server (NTRS)

    Starr, David OC. (Technical Monitor); Huffman, G. J.; Adler, R. F.; Stocker, E. F.; Bolvin, D. T.; Nelkin, E. J.

    2002-01-01

    A new processing system has been developed to combine IR and microwave data into 0.25 degree x 0.25 degree gridded precipitation estimates in near-real time over the latitude band plus or minus 50 degrees. Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) precipitation estimates are used to calibrate Special Sensor Microwave/Imager (SSM/I) estimates, and Advanced Microwave Sounding Unit (AMSU) and Advanced Microwave Scanning Radiometer (AMSR) estimates, when available. The merged microwave estimates are then used to create a calibrated IR estimate in a Probability-Matched-Threshold approach for each individual hour. The microwave and IR estimates are combined for each 3-hour interval. Early results will be shown, including typical tropical and extratropical storm evolution and examples of the diurnal cycle. Major issues will be discussed, including the choice of IR algorithm, the approach for merging the IR and microwave estimates, extension to higher latitudes, retrospective processing back to 1999, and extension to the GPCP One-Degree Daily product (for which the authors are responsible). The work described here provides one approach to using data from the future NASA Global Precipitation Measurement program, which is designed to provide Jill global coverage by low-orbit passive microwave satellites every three hours beginning around 2008.

  20. New estimates of area and mass for the North American tektite strewn field

    NASA Technical Reports Server (NTRS)

    Koeberl, C.

    1989-01-01

    A revised estimate is given for the total mass of the North American tektite material, which is based on a concept of patches or rays of distribution rather than on a continuous tektite and microtektite blanket. This concept yields a total mass of about 3 x 10 to the 14th g, which is less than a third of previous estimates. The shape of the North American tektite strewn field is in agreement with other tektite strewn fields.

  1. Applications of TRMM-based Multi-Satellite Precipitation Estimation for Global Runoff Simulation: Prototyping a Global Flood Monitoring System

    NASA Technical Reports Server (NTRS)

    Hong, Yang; Adler, Robert F.; Huffman, George J.; Pierce, Harold

    2008-01-01

    Advances in flood monitoring/forecasting have been constrained by the difficulty in estimating rainfall continuously over space (catchment-, national-, continental-, or even global-scale areas) and flood-relevant time scale. With the recent availability of satellite rainfall estimates at fine time and space resolution, this paper describes a prototype research framework for global flood monitoring by combining real-time satellite observations with a database of global terrestrial characteristics through a hydrologically relevant modeling scheme. Four major components included in the framework are (1) real-time precipitation input from NASA TRMM-based Multi-satellite Precipitation Analysis (TMPA); (2) a central geospatial database to preprocess the land surface characteristics: water divides, slopes, soils, land use, flow directions, flow accumulation, drainage network etc.; (3) a modified distributed hydrological model to convert rainfall to runoff and route the flow through the stream network in order to predict the timing and severity of the flood wave, and (4) an open-access web interface to quickly disseminate flood alerts for potential decision-making. Retrospective simulations for 1998-2006 demonstrate that the Global Flood Monitor (GFM) system performs consistently at both station and catchment levels. The GFM website (experimental version) has been running at near real-time in an effort to offer a cost-effective solution to the ultimate challenge of building natural disaster early warning systems for the data-sparse regions of the world. The interactive GFM website shows close-up maps of the flood risks overlaid on topography/population or integrated with the Google-Earth visualization tool. One additional capability, which extends forecast lead-time by assimilating QPF into the GFM, also will be implemented in the future.

  2. Cost-effective long-term groundwater monitoring design using a genetic algorithm and global mass interpolation

    NASA Astrophysics Data System (ADS)

    Reed, Patrick; Minsker, Barbara; Valocchi, Albert J.

    2000-12-01

    A new methodology for sampling plan design has been developed to reduce the costs associated with long-term monitoring of sites with groundwater contamination. The method combines a fate-and-transport model, plume interpolation, and a genetic algorithm to identify cost-effective sampling plans that accurately quantify the total mass of dissolved contaminant. The plume interpolation methods considered were inverse-distance weighting, ordinary kriging, and a hybrid method that combines the two approaches. Application of the methodology to Hill Air Force Base indicated that sampling costs could be reduced by as much as 60% without significant loss in accuracy of the global mass estimates. Inverse-distance weighting was shown to be most effective as a screening tool for evaluating whether more comprehensive geostatistical modeling is warranted. The hybrid method was effective for implementing such a tiered approach, reducing computational time by more than 60% relative to kriging alone.

  3. Estimation of cauliflower mass transfer parameters during convective drying

    NASA Astrophysics Data System (ADS)

    Sahin, Medine; Doymaz, İbrahim

    2016-05-01

    The study was conducted to evaluate the effect of pre-treatments such as citric acid and hot water blanching and air temperature on drying and rehydration characteristics of cauliflower slices. Experiments were carried out at four different drying air temperatures of 50, 60, 70 and 80 °C with the air velocity of 2.0 m/s. It was observed that drying and rehydration characteristics of cauliflower slices were greatly influenced by air temperature and pre-treatment. Six commonly used mathematical models were evaluated to predict the drying kinetics of cauliflower slices. The Midilli et al. model described the drying behaviour of cauliflower slices at all temperatures better than other models. The values of effective moisture diffusivities (D eff ) were determined using Fick's law of diffusion and were between 4.09 × 10-9 and 1.88 × 10-8 m2/s. Activation energy was estimated by an Arrhenius type equation and was 23.40, 29.09 and 26.39 kJ/mol for citric acid, blanch and control samples, respectively.

  4. Improving Global Mass Flux Solutions from Gravity Recovery and Climate Experiment (GRACE) Through Forward Modeling and Continuous Time Correlation

    NASA Technical Reports Server (NTRS)

    Sabaka, T. J.; Rowlands, D. D.; Luthcke, S. B.; Boy, J.-P.

    2010-01-01

    We describe Earth's mass flux from April 2003 through November 2008 by deriving a time series of mas cons on a global 2deg x 2deg equal-area grid at 10 day intervals. We estimate the mass flux directly from K band range rate (KBRR) data provided by the Gravity Recovery and Climate Experiment (GRACE) mission. Using regularized least squares, we take into account the underlying process dynamics through continuous space and time-correlated constraints. In addition, we place the mascon approach in the context of other filtering techniques, showing its equivalence to anisotropic, nonsymmetric filtering, least squares collocation, and Kalman smoothing. We produce mascon time series from KBRR data that have and have not been corrected (forward modeled) for hydrological processes and fmd that the former produce superior results in oceanic areas by minimizing signal leakage from strong sources on land. By exploiting the structure of the spatiotemporal constraints, we are able to use a much more efficient (in storage and computation) inversion algorithm based upon the conjugate gradient method. This allows us to apply continuous rather than piecewise continuous time-correlated constraints, which we show via global maps and comparisons with ocean-bottom pressure gauges, to produce time series with reduced random variance and full systematic signal. Finally, we present a preferred global model, a hybrid whose oceanic portions are derived using forward modeling of hydrology but whose land portions are not, and thus represent a pure GRACE-derived signal.

  5. Global Land-surface Evaporation Estimated from Satellite-based Observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper outlines a new methodology to derive evaporation from satellite observations. The approach uses a variety of satellite-sensor products to estimate daily evaporation at a global scale, with a 0.25 degree spatial resolution. Central to this approach is the use of the Priestley and Taylor (P...

  6. Improvement of sub-pixel global motion estimation in UAV image stabilization

    NASA Astrophysics Data System (ADS)

    Li, Yingjuan; Ji, Ming; He, Junfeng; Zhen, Kang; Yang, Yizhou; Chen, Ying

    2016-01-01

    Global motion estimation within frames is very important in the UAV(unmanned aerial vehicle) image stabilization system. A fast algorithm based on phase correlation and image down-sampling in sub-pixel was proposed. First, down-sampling of the two frames to quantitatively reduce calculate data. Then, take the method based of phase correlation to realize the global motion estimation in integer-pixel. When it calculated out, chooses the overlapped area of the two frames and interpolated them with zero, then adopts the method based on phase correlation to achieve the global motion estimation in sub-pixel. At last, weighted calculate the result in integer-pixel and the result in sub-pixel, the global motion displacement in sub-pixel of the two images will be calculated out. Experimental results show that, using the proposed algorithm can not only achieve good robustness to the influence of noise, illumination and partially sheltered but also improve the accuracy of motion estimation and efficiency of computing significantly.

  7. A COMPARISON OF METHODS FOR ESTIMATING GLOBAL METHANE EMISSIONS FROM LANDFILLS

    EPA Science Inventory

    Landfills are a significant source of methane, ranking third in anthropogenic sources after rice paddies and ruminants. Estimating the contribution of landfills to global methane flux is hampered by a lack of accurate refuse and landfill data, and therefore depends heavily on the...

  8. A numerical study on dust devils with implications to global dust budget estimates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The estimates of the contribution of dust devils (DDs) to the global dust budget have large uncertainties because the dust emission mechanisms in DDs are not yet well understood. In this study, a large-eddy simulation model coupled with a dust scheme is used to investigate DD dust entrainment. DDs a...

  9. Adaptive global training set selection for spectral estimation of printed inks using reflectance modeling.

    PubMed

    Eckhard, Timo; Valero, Eva M; Hernández-Andrés, Javier; Schnitzlein, Markus

    2014-02-01

    The performance of learning-based spectral estimation is greatly influenced by the set of training samples selected to create the reconstruction model. Training sample selection schemes can be categorized into global and local approaches. Most of the previously proposed global training schemes aim to reduce the number of training samples, or a selection of representative samples, to maintain the generality of the training dataset. This work relates to printed ink reflectance estimation for quality assessment in in-line print inspection. We propose what we believe is a novel global training scheme that models a large population of realistic printable ink reflectances. Based on this dataset, we used a recursive top-down algorithm to reject clusters of training samples that do not enhance the performance of a linear least-square regression (pseudoinverse-based estimation) process. A set of experiments with real camera response data of a 12-channel multispectral camera system illustrate the advantages of this selection scheme over some other state-of-the-art algorithms. For our data, our method of global training sample selection outperforms other methods in terms of estimation quality and, more importantly, can quickly handle large datasets. Furthermore, we show that reflectance modeling is a reasonable, convenient tool to generate large training sets for print inspection applications. PMID:24514188

  10. Global-Scale Location and Distance Estimates: Common Representations and Strategies in Absolute and Relative Judgments

    ERIC Educational Resources Information Center

    Friedman, Alinda; Montello, Daniel R.

    2006-01-01

    The authors examined whether absolute and relative judgments about global-scale locations and distances were generated from common representations. At the end of a 10-week class on the regional geography of the United States, participants estimated the latitudes of 16 North American cities and all possible pairwise distances between them. Although…

  11. Ambient Air Pollution Exposure Estimation for the Global Burden of Disease 2013.

    PubMed

    Brauer, Michael; Freedman, Greg; Frostad, Joseph; van Donkelaar, Aaron; Martin, Randall V; Dentener, Frank; van Dingenen, Rita; Estep, Kara; Amini, Heresh; Apte, Joshua S; Balakrishnan, Kalpana; Barregard, Lars; Broday, David; Feigin, Valery; Ghosh, Santu; Hopke, Philip K; Knibbs, Luke D; Kokubo, Yoshihiro; Liu, Yang; Ma, Stefan; Morawska, Lidia; Sangrador, José Luis Texcalac; Shaddick, Gavin; Anderson, H Ross; Vos, Theo; Forouzanfar, Mohammad H; Burnett, Richard T; Cohen, Aaron

    2016-01-01

    Exposure to ambient air pollution is a major risk factor for global disease. Assessment of the impacts of air pollution on population health and evaluation of trends relative to other major risk factors requires regularly updated, accurate, spatially resolved exposure estimates. We combined satellite-based estimates, chemical transport model simulations, and ground measurements from 79 different countries to produce global estimates of annual average fine particle (PM2.5) and ozone concentrations at 0.1° × 0.1° spatial resolution for five-year intervals from 1990 to 2010 and the year 2013. These estimates were applied to assess population-weighted mean concentrations for 1990-2013 for each of 188 countries. In 2013, 87% of the world's population lived in areas exceeding the World Health Organization Air Quality Guideline of 10 μg/m(3) PM2.5 (annual average). Between 1990 and 2013, global population-weighted PM2.5 increased by 20.4% driven by trends in South Asia, Southeast Asia, and China. Decreases in population-weighted mean concentrations of PM2.5 were evident in most high income countries. Population-weighted mean concentrations of ozone increased globally by 8.9% from 1990-2013 with increases in most countries-except for modest decreases in North America, parts of Europe, and several countries in Southeast Asia. PMID:26595236

  12. Estimation of Global 1km-grid Terrestrial Carbon Exchange Part I: Developing Inputs and Modelling

    NASA Astrophysics Data System (ADS)

    Sasai, T.; Murakami, K.; Kato, S.; Matsunaga, T.; Saigusa, N.; Hiraki, K.

    2015-12-01

    Global terrestrial carbon cycle largely depends on a spatial pattern in land cover type, which is heterogeneously-distributed over regional and global scales. However, most studies, which aimed at the estimation of carbon exchanges between ecosystem and atmosphere, remained within several tens of kilometers grid spatial resolution, and the results have not been enough to understand the detailed pattern of carbon exchanges based on ecological community. Improving the sophistication of spatial resolution is obviously necessary to enhance the accuracy of carbon exchanges. Moreover, the improvement may contribute to global warming awareness, policy makers and other social activities. In this study, we show global terrestrial carbon exchanges (net ecosystem production, net primary production, and gross primary production) with 1km-grid resolution. As methodology for computing the exchanges, we 1) developed a global 1km-grid climate and satellite dataset based on the approach in Setoyama and Sasai (2013); 2) used the satellite-driven biosphere model (Biosphere model integrating Eco-physiological And Mechanistic approaches using Satellite data: BEAMS) (Sasai et al., 2005, 2007, 2011); 3) simulated the carbon exchanges by using the new dataset and BEAMS by the use of a supercomputer that includes 1280 CPU and 320 GPGPU cores (GOSAT RCF of NIES). As a result, we could develop a global uniform system for realistically estimating terrestrial carbon exchange, and evaluate net ecosystem production in each community level; leading to obtain highly detailed understanding of terrestrial carbon exchanges.

  13. A global building inventory for earthquake loss estimation and risk management

    USGS Publications Warehouse

    Jaiswal, K.; Wald, D.; Porter, K.

    2010-01-01

    We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat's demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature. ?? 2010, Earthquake Engineering Research Institute.

  14. Estimation of Global 1km-grid Terrestrial Carbon Exchange Part II: Evaluations and Applications

    NASA Astrophysics Data System (ADS)

    Murakami, K.; Sasai, T.; Kato, S.; Niwa, Y.; Saito, M.; Takagi, H.; Matsunaga, T.; Hiraki, K.; Maksyutov, S. S.; Yokota, T.

    2015-12-01

    Global terrestrial carbon cycle largely depends on a spatial pattern in land cover type, which is heterogeneously-distributed over regional and global scales. Many studies have been trying to reveal distribution of carbon exchanges between terrestrial ecosystems and atmosphere for understanding global carbon cycle dynamics by using terrestrial biosphere models, satellite data, inventory data, and so on. However, most studies remained within several tens of kilometers grid spatial resolution, and the results have not been enough to understand the detailed pattern of carbon exchanges based on ecological community and to evaluate the carbon stocks by forest ecosystems in each countries. Improving the sophistication of spatial resolution is obviously necessary to enhance the accuracy of carbon exchanges. Moreover, the improvement may contribute to global warming awareness, policy makers and other social activities. We show global terrestrial carbon exchanges (net ecosystem production, net primary production, and gross primary production) with 1km-grid resolution. The methodology for these estimations are shown in the 2015 AGU FM poster "Estimation of Global 1km-grid Terrestrial Carbon Exchange Part I: Developing Inputs and Modelling". In this study, we evaluated the carbon exchanges in various regions with other approaches. We used the satellite-driven biosphere model (BEAMS) as our estimations, GOSAT L4A CO2 flux data, NEP retrieved by NICAM and CarbonTracer2013 flux data, for period from Jun 2001 to Dec 2012. The temporal patterns for this period were indicated similar trends between BEAMS, GOSAT, NICAM, and CT2013 in many sub-continental regions. Then, we estimated the terrestrial carbon exchanges in each countries, and could indicated the temporal patterns of the exchanges in large carbon stock regions.Global terrestrial carbon cycle largely depends on a spatial pattern of land cover type, which is heterogeneously-distributed over regional and global scales. Many

  15. WHE-PAGER Project: A new initiative in estimating global building inventory and its seismic vulnerability

    USGS Publications Warehouse

    Porter, K.A.; Jaiswal, K.S.; Wald, D.J.; Greene, M.; Comartin, Craig

    2008-01-01

    The U.S. Geological Survey’s Prompt Assessment of Global Earthquake’s Response (PAGER) Project and the Earthquake Engineering Research Institute’s World Housing Encyclopedia (WHE) are creating a global database of building stocks and their earthquake vulnerability. The WHE already represents a growing, community-developed public database of global housing and its detailed structural characteristics. It currently contains more than 135 reports on particular housing types in 40 countries. The WHE-PAGER effort extends the WHE in several ways: (1) by addressing non-residential construction; (2) by quantifying the prevalence of each building type in both rural and urban areas; (3) by addressing day and night occupancy patterns, (4) by adding quantitative vulnerability estimates from judgment or statistical observation; and (5) by analytically deriving alternative vulnerability estimates using in part laboratory testing.

  16. A First Approach to Global Runoff Simulation using Satellite Rainfall Estimation

    NASA Technical Reports Server (NTRS)

    Hong, Yang; Adler, Robert F.; Hossain, Faisal; Curtis, Scott; Huffman, George J.

    2007-01-01

    Many hydrological models have been introduced in the hydrological literature to predict runoff but few of these have become common planning or decision-making tools, either because the data requirements are substantial or because the modeling processes are too complicated for operational application. On the other hand, progress in regional or global rainfall-runoff simulation has been constrained by the difficulty of measuring spatiotemporal variability of the primary causative factor, i.e. rainfall fluxes, continuously over space and time. Building on progress in remote sensing technology, researchers have improved the accuracy, coverage, and resolution of rainfall estimates by combining imagery from infrared, passive microwave, and space-borne radar sensors. Motivated by the recent increasing availability of global remote sensing data for estimating precipitation and describing land surface characteristics, this note reports a ballpark assessment of quasi-global runoff computed by incorporating satellite rainfall data and other remote sensing products in a relatively simple rainfall-runoff simulation approach: the Natural Resources Conservation Service (NRCS) runoff Curve Number (CN) method. Using an Antecedent Precipitation Index (API) as a proxy of antecedent moisture conditions, this note estimates time-varying NRCS-CN values determined by the 5-day normalized API. Driven by multi-year (1998-2006) Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis, quasi-global runoff was retrospectively simulated with the NRCS-CN method and compared to Global Runoff Data Centre data at global and catchment scales. Results demonstrated the potential for using this simple method when diagnosing runoff values from satellite rainfall for the globe and for medium to large river basins. This work was done with the simple NRCS-CN method as a first-cut approach to understanding the challenges that lie ahead in advancing the satellite-based inference of

  17. IMPROVED METHOD FOR ESTIMATING MOLECULAR WEIGHTS OF VOLATILE ORGANIC COMPOUNDS FROM LOW RESOLUTION MASS SPECTRA

    EPA Science Inventory

    An improved method of estimating molecular weights of volatile organic compound from their mass spectra has been developed and implemented with an expert system. he method is based on the strong correlation of MAXMASS, the highest mass with an intensity of 5% of the base peak in ...

  18. Effect of body composition methodology on estimates of fat mass heritability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Body fatness is influenced by both genetic and environmental factors. Previous studies have produced a wide range of estimates for the heritability of body fatness, ranging from 0.34-0.90 for body mass index (BMI), 0.59-0.83 for percent body fat, and 0.45-0.71 for fat mass. Little atte...

  19. Estimating flow properties of quasi-newtonian mass-movements

    NASA Astrophysics Data System (ADS)

    Barnouin-Jha, O. S.; Bulmer, M.; Baloga, S.; Glaze, L.

    2001-12-01

    A variety of models exist in the literature to describe the flow behavior and rheological nature of debris flows. These include viscoplastic models, inertial grain flow models, fluid-solid momentum transport models and empirical Chezy-type models. For the purpose of planetary studies, the Chezy-type models have been found very useful. These models make few apriori assumptions on the physical processes ongoing in a debris flow, but rather parameterize the momentum transport and energy dissipation of debris flows with semi-empirical constants. When properly calibrated with appropriate field and laboratory evidence, these constants can provide a first order qualitative view into the behavior and rheological character, particularly water content, of a debris flow. Such a view permits the development and use of the more sophisticated debris flow models mentioned above where the physical processes are explicitly accounted for and from which, in conjunction with observation, quantitative rheological parameters can be determined. The strength of the Chezy-type models lies in that its parameterizing constants can be derived relatively easily from topographic data and airborne or space-based imaging and compared with a large body of terrestrial analogs. In this study, we will use a form of the Chezy model commonly applied to investigate quasi-Newtonian flows that are fast moving fluids bearing various kinds of loading or suspension. We will present a list of the Chezy constants for a wide-range of debris flows, ranging from water to water-rich landslides. This calibration table was determined by completing a literature search where velocity, channel slope, channel cross-sectional area, channel width and rheological characteristics of the debris flows were available. We show how rheological inferences, particularly water- content of one type of mass movement - debris flows - can be constrained using planetary data sets. These inferences are derived through judicious use of

  20. Yellow Fever in Africa: Estimating the Burden of Disease and Impact of Mass Vaccination from Outbreak and Serological Data

    PubMed Central

    Garske, Tini; Van Kerkhove, Maria D.; Yactayo, Sergio; Ronveaux, Olivier; Lewis, Rosamund F.; Staples, J. Erin; Perea, William; Ferguson, Neil M.

    2014-01-01

    Background Yellow fever is a vector-borne disease affecting humans and non-human primates in tropical areas of Africa and South America. While eradication is not feasible due to the wildlife reservoir, large scale vaccination activities in Africa during the 1940s to 1960s reduced yellow fever incidence for several decades. However, after a period of low vaccination coverage, yellow fever has resurged in the continent. Since 2006 there has been substantial funding for large preventive mass vaccination campaigns in the most affected countries in Africa to curb the rising burden of disease and control future outbreaks. Contemporary estimates of the yellow fever disease burden are lacking, and the present study aimed to update the previous estimates on the basis of more recent yellow fever occurrence data and improved estimation methods. Methods and Findings Generalised linear regression models were fitted to a dataset of the locations of yellow fever outbreaks within the last 25 years to estimate the probability of outbreak reports across the endemic zone. Environmental variables and indicators for the surveillance quality in the affected countries were used as covariates. By comparing probabilities of outbreak reports estimated in the regression with the force of infection estimated for a limited set of locations for which serological surveys were available, the detection probability per case and the force of infection were estimated across the endemic zone. The yellow fever burden in Africa was estimated for the year 2013 as 130,000 (95% CI 51,000–380,000) cases with fever and jaundice or haemorrhage including 78,000 (95% CI 19,000–180,000) deaths, taking into account the current level of vaccination coverage. The impact of the recent mass vaccination campaigns was assessed by evaluating the difference between the estimates obtained for the current vaccination coverage and for a hypothetical scenario excluding these vaccination campaigns. Vaccination campaigns

  1. A New Method for Estimating the Coverage of Mass Vaccination Campaigns Against Poliomyelitis From Surveillance Data.

    PubMed

    O'Reilly, K M; Cori, A; Durry, E; Wadood, M Z; Bosan, A; Aylward, R B; Grassly, N C

    2015-12-01

    Mass vaccination campaigns with the oral poliovirus vaccine targeting children aged <5 years are a critical component of the global poliomyelitis eradication effort. Monitoring the coverage of these campaigns is essential to allow corrective action, but current approaches are limited by their cross-sectional nature, nonrandom sampling, reporting biases, and accessibility issues. We describe a new Bayesian framework using data augmentation and Markov chain Monte Carlo methods to estimate variation in vaccination coverage from children's vaccination histories investigated during surveillance for acute flaccid paralysis. We tested the method using simulated data with at least 200 cases and were able to detect undervaccinated groups if they exceeded 10% of all children and temporal changes in coverage of ±10% with greater than 90% sensitivity. Application of the method to data from Pakistan for 2010-2011 identified undervaccinated groups within the Balochistan/Federally Administered Tribal Areas and Khyber Pakhtunkhwa regions, as well as temporal changes in coverage. The sizes of these groups are consistent with the multiple challenges faced by the program in these regions as a result of conflict and insecurity. Application of this new method to routinely collected data can be a useful tool for identifying poorly performing areas and assisting in eradication efforts. PMID:26568569

  2. A New Method for Estimating the Coverage of Mass Vaccination Campaigns Against Poliomyelitis From Surveillance Data

    PubMed Central

    O'Reilly, K. M.; Cori, A.; Durry, E.; Wadood, M. Z.; Bosan, A.; Aylward, R. B.; Grassly, N. C.

    2015-01-01

    Mass vaccination campaigns with the oral poliovirus vaccine targeting children aged <5 years are a critical component of the global poliomyelitis eradication effort. Monitoring the coverage of these campaigns is essential to allow corrective action, but current approaches are limited by their cross-sectional nature, nonrandom sampling, reporting biases, and accessibility issues. We describe a new Bayesian framework using data augmentation and Markov chain Monte Carlo methods to estimate variation in vaccination coverage from children's vaccination histories investigated during surveillance for acute flaccid paralysis. We tested the method using simulated data with at least 200 cases and were able to detect undervaccinated groups if they exceeded 10% of all children and temporal changes in coverage of ±10% with greater than 90% sensitivity. Application of the method to data from Pakistan for 2010–2011 identified undervaccinated groups within the Balochistan/Federally Administered Tribal Areas and Khyber Pakhtunkhwa regions, as well as temporal changes in coverage. The sizes of these groups are consistent with the multiple challenges faced by the program in these regions as a result of conflict and insecurity. Application of this new method to routinely collected data can be a useful tool for identifying poorly performing areas and assisting in eradication efforts. PMID:26568569

  3. Phobos mass estimations from MEX and Viking 1 data: influence of different noise sources and estimation strategies

    NASA Astrophysics Data System (ADS)

    Kudryashova, M.; Rosenblatt, P.; Marty, J.-C.

    2015-08-01

    The mass of Phobos is an important parameter which, together with second-order gravity field coefficients and libration amplitude, constrains internal structure and nature of the moon. And thus, it needs to be known with high precision. Nevertheless, Phobos mass (GM, more precisely) estimated by different authors based on diverse data-sets and methods, varies by more than their 1-sigma error. The most complete lists of GM values are presented in the works of R. Jacobson (2010) and M. Paetzold et al. (2014) and include the estimations in the interval from (5.39 ± 0:03).10^5 (Smith et al., 1995) till (8.5 ± 0.7).10^5[m^3/s^2] (Williams et al., 1988). Furthermore, even the comparison of the estimations coming from the same estimation procedure applied to the consecutive flybys of the same spacecraft (s/c) shows big variations in GMs. The indicated behavior is very pronounced in the GM estimations stemming from the Viking1 flybys in February 1977 (as well as from MEX flybys, though in a smaller amplitude) and in this work we made an attempt to figure out its roots. The errors of Phobos GM estimations depend on the precision of the model (e.g. accuracy of Phobos a priori ephemeris and its a priori GM value) as well as on the radio-tracking measurements quality (noise, coverage, flyby distance). In the present work we are testing the impact of mentioned above error sources by means of simulations. We also consider the effect of the uncertainties in a priori Phobos positions on the GM estimations from real observations. Apparently, the strategy (i.e. splitting real observations in data-arcs, whether they stem from the close approaches of Phobos by spacecraft or from analysis of the s/c orbit evolution around Mars) of the estimations has an impact on the Phobos GM estimation.

  4. Assessment of the Global Monthly Mean Surface Insolation Estimated from Satellite Measurements Using Global Energy Balance Archive Data.

    NASA Astrophysics Data System (ADS)

    Li, Zhanqing; Whitlock, Charles H.; Charlock, Thomas P.

    1995-02-01

    Global datasets of surface radiation budget (SRB) have been obtained from satellite programs. These satellite-based estimates need validation with ground-truth observations. This study validates the estimates of monthly mean surface insolation contained in two satellite-based SRB datasets with the surface measurements made at worldwide radiation stations from the Global Energy Balance Archive (GEBA). One dataset was developed from the Earth Radiation Budget Experiment (ERBE) using the algorithm of Li et al. (ERBE/SRB), and the other from the International Satellite Cloud Climatology Project (ISCCP) using the algorithm of Pinker and Laszlo and that of Staylor (GEWEX/SRB). Since the ERBE/SRB data contain the surface net solar radiation only, the values of surface insolation were derived by making use of the surface albedo data contained in the GEWEX/SRB product. The resulting surface insolation has a bias error near zero and a root-mean-square error (RMSE) between 8 and 28 W m2. The RMSE is mainly associated with poor representation of surface observations within a grid cell. When the number of surface observations are sufficient, the random error is estimated to be about 5 W m2 with present satellite-based estimates. In addition to demonstrating the strength of the retrieving method, the small random error demonstrates how well the ERBE derives the monthly mean fluxes at the top of the atmosphere (TOA). A larger scatter is found for the comparison of transmissivity than for that of insolation. Month to month comparison of insolation reveals a weak seasonal trend in bias error with an amplitude of about 3 W m2. As for the insolation data from the GEWEX/SRB, larger bias errors of 5-10 W m2 are evident with stronger seasonal trends and almost identical RMSEs.

  5. Assessment of the global monthly mean surface insolation estimated from satellite measurements using global energy balance archive data

    NASA Technical Reports Server (NTRS)

    Li, Zhanqing; Whitlock, Charles H.; Charlock, Thomas P.

    1995-01-01

    Global sets of surface radiation budget (SRB) have been obtained from satellite programs. These satellite-based estimates need validation with ground-truth observations. This study validates the estimates of monthly mean surface insolation contained in two satellite-based SRB datasets with the surface measurements made at worldwide radiation stations from the Global Energy Balance Archive (GEBA). One dataset was developed from the Earth Radiation Budget Experiment (ERBE) using the algorithm of Li et al. (ERBE/SRB), and the other from the International Satellite Cloud Climatology Project (ISCCP) using the algorithm of Pinker and Laszlo and that of Staylor (GEWEX/SRB). Since the ERBE/SRB data contain the surface net solar radiation only, the values of surface insolation were derived by making use of the surface albedo data contained GEWEX/SRB product. The resulting surface insolation has a bias error near zero and a root-mean-square error (RMSE) between 8 and 28 W/sq m. The RMSE is mainly associated with poor representation of surface observations within a grid cell. When the number of surface observations are sufficient, the random error is estimated to be about 5 W/sq m with present satellite-based estimates. In addition to demonstrating the strength of the retrieving method, the small random error demonstrates how well the ERBE derives from the monthly mean fluxes at the top of the atmosphere (TOA). A larger scatter is found for the comparison of transmissivity than for that of insolation. Month to month comparison of insolation reveals a weak seasonal trend in bias error with an amplitude of about 3 W/sq m. As for the insolation data from the GEWEX/SRB, larger bias errors of 5-10 W/sq m are evident with stronger seasonal trends and almost identical RMSEs.

  6. Recharge Estimation Using Water, Chloride and Isotope Mass Balances

    NASA Astrophysics Data System (ADS)

    Dogramaci, S.; Firmani, G.; Hedley, P.; Skrzypek, G.; Grierson, P. F.

    2014-12-01

    Discharge of surplus mine water into ephemeral streams may elevate groundwater levels and alter the exchange rate between streams and underlying aquifers but it is unclear whether volumes and recharge processes are within the range of natural variability. Here, we present a case study of an ephemeral creek in the semi-arid subtropical Hamersley Basin that has received continuous mine discharge for more than five years. We used a numerical model coupled with repeated measurements of water levels, chloride concentrations and the hydrogen and oxygen stable isotope composition (δ2H and δ18O) to estimate longitudinal evapotranspiration and recharge rates along a 27 km length of Weeli Wolli Creek. We found that chloride increased from 74 to 120 mg/L across this length, while δ18O increased from -8.24‰ to -7.00‰. Groundwater is directly connected to the creek for the first 13 km and recharge rates are negligible. Below this point, the creek flows over a highly permeable aquifer and water loss by recharge increases to a maximum rate of 4.4 mm/d, which accounts for ~ 65% of the total water discharged to the creek. Evapotranspiration losses account for the remaining ~35%. The calculated recharge from continuous flow due to surplus water discharge is similar to that measured for rainfall-driven flood events along the creek. Groundwater under the disconnected section of the creek is characterised by a much lower Cl concentration and more depleted δ18O value than mining discharge water but is similar to flood water generated by large episodic rainfall events. Our results suggest that the impact of recharge from continuous flow on the creek has not extended beyond 27 km from the discharge point. Our approach using a combination of hydrochemical and isotope methods coupled with classical surface flow hydraulic modelling allowed evaluation of components of water budget otherwise not possible in a highly dynamic system that is mainly driven by infrequent but large episodic

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  8. A New Fine-Scale, Quasi-Global Combined Precipitation Estimate Based on TRMM

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, R. F.; Bolvin, D. T.; Nelkin, E. J.; Starr, David OC. (Technical Monitor)

    2001-01-01

    A TRMM-based 3-hourly precipitation algorithm is currently under development, with the goal of producing 0.25 deg x 0.25 deg, 3-hourly gridded estimates for the period January 1999 to the present over the latitude band +/-50 deg. [Extension to higher latitudes will be undertaken next]. TMI precipitation estimates are used to calibrate SSM/I estimates, and AMSR, when available. Then a merger of the microwave estimates is used to create a calibrated IR estimate in a Probability-Matched-Threshold approach. The microwave and IR estimates are next combined at the individual 3-hour level. Early results will be shown, including typical tropical and extratropical storm evolution and examples of the diurnal cycle. Major issues will be discussed, including the choice of IR algorithm, the approach to merging the IR and microwave estimates, and extension to the GPCP One-Degree Daily product (for which the authors are responsible). The work described here provides one approach to using data from the future NASA Global Precipitation Measurement program, which is designed to provide full global coverage by low-orbit passive microwave satellites every three hours beginning around 2007.

  9. Methodological Framework for World Health Organization Estimates of the Global Burden of Foodborne Disease

    PubMed Central

    Devleesschauwer, Brecht; Haagsma, Juanita A.; Angulo, Frederick J.; Bellinger, David C.; Cole, Dana; Döpfer, Dörte; Fazil, Aamir; Fèvre, Eric M.; Gibb, Herman J.; Hald, Tine; Kirk, Martyn D.; Lake, Robin J.; Maertens de Noordhout, Charline; Mathers, Colin D.; McDonald, Scott A.; Pires, Sara M.; Speybroeck, Niko; Thomas, M. Kate; Torgerson, Paul R.; Wu, Felicia; Havelaar, Arie H.; Praet, Nicolas

    2015-01-01

    Background The Foodborne Disease Burden Epidemiology Reference Group (FERG) was established in 2007 by the World Health Organization to estimate the global burden of foodborne diseases (FBDs). This paper describes the methodological framework developed by FERG's Computational Task Force to transform epidemiological information into FBD burden estimates. Methods and Findings The global and regional burden of 31 FBDs was quantified, along with limited estimates for 5 other FBDs, using Disability-Adjusted Life Years in a hazard- and incidence-based approach. To accomplish this task, the following workflow was defined: outline of disease models and collection of epidemiological data; design and completion of a database template; development of an imputation model; identification of disability weights; probabilistic burden assessment; and estimating the proportion of the disease burden by each hazard that is attributable to exposure by food (i.e., source attribution). All computations were performed in R and the different functions were compiled in the R package 'FERG'. Traceability and transparency were ensured by sharing results and methods in an interactive way with all FERG members throughout the process. Conclusions We developed a comprehensive framework for estimating the global burden of FBDs, in which methodological simplicity and transparency were key elements. All the tools developed have been made available and can be translated into a user-friendly national toolkit for studying and monitoring food safety at the local level. PMID:26633883

  10. Estimating Climatological Bias Errors for the Global Precipitation Climatology Project (GPCP)

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Gu, Guojun; Huffman, George

    2012-01-01

    A procedure is described to estimate bias errors for mean precipitation by using multiple estimates from different algorithms, satellite sources, and merged products. The Global Precipitation Climatology Project (GPCP) monthly product is used as a base precipitation estimate, with other input products included when they are within +/- 50% of the GPCP estimates on a zonal-mean basis (ocean and land separately). The standard deviation s of the included products is then taken to be the estimated systematic, or bias, error. The results allow one to examine monthly climatologies and the annual climatology, producing maps of estimated bias errors, zonal-mean errors, and estimated errors over large areas such as ocean and land for both the tropics and the globe. For ocean areas, where there is the largest question as to absolute magnitude of precipitation, the analysis shows spatial variations in the estimated bias errors, indicating areas where one should have more or less confidence in the mean precipitation estimates. In the tropics, relative bias error estimates (s/m, where m is the mean precipitation) over the eastern Pacific Ocean are as large as 20%, as compared with 10%-15% in the western Pacific part of the ITCZ. An examination of latitudinal differences over ocean clearly shows an increase in estimated bias error at higher latitudes, reaching up to 50%. Over land, the error estimates also locate regions of potential problems in the tropics and larger cold-season errors at high latitudes that are due to snow. An empirical technique to area average the gridded errors (s) is described that allows one to make error estimates for arbitrary areas and for the tropics and the globe (land and ocean separately, and combined). Over the tropics this calculation leads to a relative error estimate for tropical land and ocean combined of 7%, which is considered to be an upper bound because of the lack of sign-of-the-error canceling when integrating over different areas with a

  11. The impact of global nuclear mass model uncertainties on r-process abundance predictions

    NASA Astrophysics Data System (ADS)

    Mumpower, M.; Surman, R.; Aprahamian, A.

    2015-05-01

    Rapid neutron capture or `r-process' nucleosynthesis may be responsible for half the production of heavy elements above iron on the periodic table. Masses are one of the most important nuclear physics ingredients that go into calculations of r-process nucleosynthesis as they enter into the calculations of reaction rates, decay rates, branching ratios and Q-values. We explore the impact of uncertainties in three nuclear mass models on r-process abundances by performing global monte carlo simulations. We show that root-mean-square (rms) errors of current mass models are large so that current r-process predictions are insufficient in predicting features found in solar residuals and in r-process enhanced metal poor stars. We conclude that the reduction of global rms errors below 100 keV will allow for more robust r-process predictions.

  12. Optimization of regional constraints for estimating the Greenland mass balance with GRACE level-2 data

    NASA Astrophysics Data System (ADS)

    Xu, Z.; Schrama, E.; van der Wal, W.

    2015-07-01

    Data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission can be used to estimate the mass change rate for separate drainage systems (DSs) of the Greenland Ice Sheet (GrIS). One approach to do so is by inversion of the level-2 spherical harmonic data to surface mass changes in predefined regions, or mascons. However, the inversion can be numerically unstable for some individual DSs. This occurs mainly for DSs with a small mass change signal that are located in the interior region of Greenland. In this study, we present a modified mascon inversion approach with an improved implementation of the constraint equations to obtain better estimates for individual DSs. We use separate constraints for mass change variability in the coastal zone, where run-off takes place, and for the ice sheet interior above 2000 m, where mass changes are smaller. A multi-objective optimization approach is used to find optimal prior variances for these two areas based on a simulation model. Correlations between adjacent DSs are suppressed when our optimized prior variances are used, while the mass balance estimates for the combination of the DSs that make up the GrIS above 2000 m are not affected significantly. The resulting mass balance estimates for some DSs in the interior are significantly improved compared to an inversion with a single constraint, as determined by a comparison with mass balance estimates from surface mass balance modelling and discharge measurements. The rate of mass change of the GrIS for the period of January 2003 to December 2012 is found to be -266.1 ± 17.2 Gt yr-1 in the coastal zone and areas below 2000 m, and +8.2 ± 8.6 Gt yr-1 in the interior region.

  13. Estimating the fossil disc mass during supermassive black hole mergers: the importance of torque implementation

    NASA Astrophysics Data System (ADS)

    Tazzari, M.; Lodato, G.

    2015-05-01

    In this paper, we revisit the issue of estimating the `fossil' disc mass in the circumprimary disc, during the merger of a supermassive black hole binary. As the binary orbital decay speeds up due to the emission of gravitational waves, the gas in the circumprimary disc might be forced to accrete rapidly and could in principle provide a significant electromagnetic counterpart to the gravitational wave emission. Since the luminosity of such flare is proportional to the gaseous mass in the circumprimary disc, estimating such mass accurately is important. Previous investigations of this issue have produced contradictory results, with some authors estimating super-Eddington flares and large disc mass, while others suggesting that the `fossil' disc mass is very low, even less than a Jupiter mass. Here, we perform simple 1D calculations to show that such very low estimates of the disc mass are an artefact of the specific implementation of the tidal torque in 1D models. In particular, for moderate mass ratios of the binary, the usual formula for the torque used in 1D models significantly overestimates the width of the gap induced by the secondary and this artificially leads to a very small leftover circumprimary disc. Using a modified torque, calibrated to reproduce the correct gap width as estimated by 3D models, leads to fossil disc masses of the order of one solar mass. The rapid accretion of the whole circumprimary disc would produce peak luminosities of the order of 1-20 times the Eddington luminosity. Even if a significant fraction of the gas escapes accretion by flowing out the secondary orbit during the merger (an effect not included in our calculations), we would still predict close to Eddington luminosities that might be easily detected.

  14. Towards an estimation of water masses formation areas from SMOS-based TS diagrams

    NASA Astrophysics Data System (ADS)

    Klockmann, Marlene; Sabia, Roberto; Fernandez-Prieto, Diego; Donlon, Craig; Font, Jordi

    2014-05-01

    Temperature-Salinity (TS) diagrams emphasize the mutual variability of ocean temperature and salinity values, relating them to the corresponding density. Canonically used in oceanography, they provide a means to characterize and trace ocean water masses. In [1], a first attempt to estimate surface-layer TS diagrams based on satellite measurements has been performed, profiting from the recent availability of spaceborne salinity data. In fact, the Soil Moisture and Ocean Salinity (SMOS, [2]) and the Aquarius/SAC-D [3] satellite missions allow to study the dynamical patterns of Sea Surface Salinity (SSS) for the first time on a global scale. In [4], given SMOS and Aquarius salinity estimates, and by also using Sea Surface Temperature (SST) from the Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA, [5]) effort, experimental satellite-based TS diagrams have been routinely derived for the year 2011. They have been compared with those computed from ARGO-buoys interpolated fields, referring to a customised partition of the global ocean into seven regions, according to the water masses classification of [6]. In [7], moreover, besides using TS diagrams as a diagnostic tool to evaluate the temporal variation of SST and SSS (and their corresponding density) as estimated by satellite measurements, the emphasis was on the interpretation of the geographical deviations with respect to the ARGO baseline (aiming at distinguishing between the SSS retrieval errors and the additional information contained in the satellite data with respect to ARGO). In order to relate these mismatches to identifiable oceanographic structures and processes, additional satellite datasets of ocean currents, evaporation/precipitation fluxes, and wind speed have been super-imposed. Currently, the main focus of the study deals with the exploitation of these TS diagrams as a prognostic tool to derive water masses formation areas. Firstly, following the approach described in [8], the surface

  15. Synthesizing Global and Local Datasets to Estimate Jurisdictional Forest Carbon Fluxes in Berau, Indonesia

    PubMed Central

    Griscom, Bronson W.; Ellis, Peter W.; Baccini, Alessandro; Marthinus, Delon; Evans, Jeffrey S.; Ruslandi

    2016-01-01

    Background Forest conservation efforts are increasingly being implemented at the scale of sub-national jurisdictions in order to mitigate global climate change and provide other ecosystem services. We see an urgent need for robust estimates of historic forest carbon emissions at this scale, as the basis for credible measures of climate and other benefits achieved. Despite the arrival of a new generation of global datasets on forest area change and biomass, confusion remains about how to produce credible jurisdictional estimates of forest emissions. We demonstrate a method for estimating the relevant historic forest carbon fluxes within the Regency of Berau in eastern Borneo, Indonesia. Our method integrates best available global and local datasets, and includes a comprehensive analysis of uncertainty at the regency scale. Principal Findings and Significance We find that Berau generated 8.91 ± 1.99 million tonnes of net CO2 emissions per year during 2000–2010. Berau is an early frontier landscape where gross emissions are 12 times higher than gross sequestration. Yet most (85%) of Berau’s original forests are still standing. The majority of net emissions were due to conversion of native forests to unspecified agriculture (43% of total), oil palm (28%), and fiber plantations (9%). Most of the remainder was due to legal commercial selective logging (17%). Our overall uncertainty estimate offers an independent basis for assessing three other estimates for Berau. Two other estimates were above the upper end of our uncertainty range. We emphasize the importance of including an uncertainty range for all parameters of the emissions equation to generate a comprehensive uncertainty estimate–which has not been done before. We believe comprehensive estimates of carbon flux uncertainty are increasingly important as national and international institutions are challenged with comparing alternative estimates and identifying a credible range of historic emissions values

  16. Methane Emissions From Global Paddy Rice Agriculture - a New Estimate Based on DNDC Model Simulations

    NASA Astrophysics Data System (ADS)

    Hagen, S. C.; Li, C.; Salas, W.; Ingraham, P.; Li, J.; Beach, R.; Frolking, S.

    2012-12-01

    Roughly one-quarter of global methane emissions to the atmosphere come from the agricultural sector. Agricultural emissions are dominated by livestock (ruminants) and paddy-rice agriculture. We report on a new estimate of global methane emissions from paddy rice c.2010, based on DNDC model simulations of rice cropping around the world. We first generated a global map of rice cropping at 0.5°-resolution, based on existing global crop maps and various other published data. For each 0.5° grid cell that has rice agriculture, we simulated all rice cropping systems that our mapping indicated to be occurring there - irrigated and/or rainfed; single-rice, double-rice, triple-rice, and/or rice-rotated with other upland crops - under local climate and soil conditions, with assumptions about crop management (e.g., fertilizer type and amount, irrigation, flooding frequency and duration, manure application, tillage, crop residue management). We estimate global paddy rice emissions at 23 Tg CH4/yr from 120 Mha of rice paddies (land area) and 160 Mha of rice cropping (harvested area) for the baseline management scenario. We also report on the spatial distribution of these emissions, and the impacts of various management alternatives (flooding methods, fertilizer types, crop residue incorporation etc.) on yield, soil carbon sequestration and emissions of methane and nitrous oxide. For example, simulations with continuous flooding on all paddies increased simulated global paddy rice emissions to 33 Tg CH4/yr, while simulations where all fertilizer was applied as ammonium sulfate reduced simulated global paddy rice emissions to about 19 Tg CH4/yr. Simulated global paddy rice yield was about 320 Tg C in grain.

  17. A New Estimation of Global Soil Greenhouse Gas Fluxes Using a Simple Data-Oriented Model

    PubMed Central

    Hashimoto, Shoji

    2012-01-01

    Soil greenhouse gas fluxes (particularly CO2, CH4, and N2O) play important roles in climate change. However, despite the importance of these soil greenhouse gases, the number of reports on global soil greenhouse gas fluxes is limited. Here, new estimates are presented for global soil CO2 emission (total soil respiration), CH4 uptake, and N2O emission fluxes, using a simple data-oriented model. The estimated global fluxes for CO2 emission, CH4 uptake, and N2O emission were 78 Pg C yr−1 (Monte Carlo 95% confidence interval, 64–95 Pg C yr−1), 18 Tg C yr−1 (11–23 Tg C yr−1), and 4.4 Tg N yr−1 (1.4–11.1 Tg N yr−1), respectively. Tropical regions were the largest contributor of all of the gases, particularly the CO2 and N2O fluxes. The soil CO2 and N2O fluxes had more pronounced seasonal patterns than the soil CH4 flux. The collected estimates, including both the previous and the present estimates, demonstrate that the means of the best estimates from each study were 79 Pg C yr−1 (291 Pg CO2 yr−1; coefficient of variation, CV = 13%, N = 6) for CO2, 21 Tg C yr−1 (29 Tg CH4 yr−1; CV = 24%, N = 24) for CH4, and 7.8 Tg N yr−1 (12.2 Tg N2O yr−1; CV = 38%, N = 11) for N2O. For N2O, the mean of the estimates that was calculated by excluding the earliest two estimates was 6.6 Tg N yr−1 (10.4 Tg N2O yr−1; CV = 22%, N = 9). The reported estimates vary and have large degrees of uncertainty but their overall magnitudes are in general agreement. To further minimize the uncertainty of soil greenhouse gas flux estimates, it is necessary to build global databases and identify key processes in describing global soil greenhouse gas fluxes. PMID:22876295

  18. Global lightning NOx production estimated by an assimilation of multiple satellite data sets

    NASA Astrophysics Data System (ADS)

    Miyazaki, K.; Eskes, H. J.; Sudo, K.; Zhang, C.

    2014-04-01

    The global source of lightning-produced NOx (LNOx) is estimated by assimilating observations of NO2, O3, HNO3, and CO measured by multiple satellite measurements into a chemical transport model. Included are observations from the Ozone Monitoring Instrument (OMI), Microwave Limb Sounder (MLS), Tropospheric Emission Spectrometer (TES), and Measurements of Pollution in the Troposphere (MOPITT) instruments. The assimilation of multiple chemical data sets with different vertical sensitivity profiles provides comprehensive constraints on the global LNOx source while improving the representations of the entire chemical system affecting atmospheric NOx, including surface emissions and inflows from the stratosphere. The annual global LNOx source amount and NO production efficiency are estimated at 6.3 Tg N yr-1 and 310 mol NO flash-1, respectively. Sensitivity studies with perturbed satellite data sets, model and data assimilation settings lead to an error estimate of about 1.4 Tg N yr-1 on this global LNOx source. These estimates are significantly different from those estimated from a parameter inversion that optimizes only the LNOx source from NO2 observations alone, which may lead to an overestimate of the source adjustment. The total LNOx source is predominantly corrected by the assimilation of OMI NO2 observations, while TES and MLS observations add important constraints on the vertical source profile. The results indicate that the widely used lightning parameterization based on the C-shape assumption underestimates the source in the upper troposphere and overestimates the peak source height by up to about 1 km over land and the tropical western Pacific. Adjustments are larger over ocean than over land, suggesting that the cloud height dependence is too weak over the ocean in the Price and Rind (1992) approach. The significantly improved agreement between the analyzed ozone fields and independent observations gives confidence in the performance of the LNOx source

  19. Experimental design for estimating parameters of rate-limited mass transfer: Analysis of stream tracer studies

    USGS Publications Warehouse

    Wagner, B.J.; Harvey, J.W.

    1997-01-01

    Tracer experiments are valuable tools for analyzing the transport characteristics of streams and their interactions with shallow groundwater. The focus of this work is the design of tracer studies in high-gradient stream systems subject to advection, dispersion, groundwater inflow, and exchange between the active channel and zones in surface or subsurface water where flow is stagnant or slow moving. We present a methodology for (1) evaluating and comparing alternative stream tracer experiment designs and (2) identifying those combinations of stream transport properties that pose limitations to parameter estimation and therefore a challenge to tracer test design. The methodology uses the concept of global parameter uncertainty analysis, which couples solute transport simulation with parameter uncertainty analysis in a Monte Carlo framework. Two general conclusions resulted from this work. First, the solute injection and sampling strategy has an important effect on the reliability of transport parameter estimates. We found that constant injection with sampling through concentration rise, plateau, and fall provided considerably more reliable parameter estimates than a pulse injection across the spectrum of transport scenarios likely encountered in high-gradient streams. Second, for a given tracer test design, the uncertainties in mass transfer and storage-zone parameter estimates are strongly dependent on the experimental Damkohler number, DaI, which is a dimensionless combination of the rates of exchange between the stream and storage zones, the stream-water velocity, and the stream reach length of the experiment. Parameter uncertainties are lowest at DaI values on the order of 1.0. When DaI values are much less than 1.0 (owing to high velocity, long exchange timescale, and/or short reach length), parameter uncertainties are high because only a small amount of tracer interacts with storage zones in the reach. For the opposite conditions (DaI >> 1.0), solute exchange

  20. Spurious barometric pressure acceleration in Antarctica and propagation into GRACE Antarctic mass change estimates

    NASA Astrophysics Data System (ADS)

    Kim, Byeong-Hoon; Eom, Jooyoung; Seo, Ki-Weon; Wilson, Clark R.

    2016-06-01

    Apparent acceleration in GRACE Antarctic ice mass time series may reflect both ice discharge and surface mass balance contributions. However, a recent study suggests there is also contamination from errors in atmospheric pressure de-aliasing fields (ECMWF operational products) used during GRACE data processing. To further examine this question, we compare GRACE atmospheric pressure de-aliasing (GAA) fields with in-situ surface pressure data from coastal and inland stations. Differences between the two are likely due to GAA errors, and provide a measure of error in GRACE solutions. Time series of differences at individual weather stations are fit to four presumed error components: annual sinusoids, a linear trend, an acceleration term, and jumps at times of known ECMWF model changes. Using data from inland stations, we estimate that atmospheric pressure error causes an acceleration error of about +7.0 Gt/yr2, which is large relative to prior GRACE estimates of Antarctic ice mass acceleration in the range of -12 to -14 Gt/yr2. We also estimate apparent acceleration rates from other barometric pressure (reanalysis) fields, including ERA-Interim, MERRA and NCEP/DOE. When integrated over East Antarctica, the four mass acceleration estimates (from GAA and the three reanalysis fields) vary considerably (by ˜2-16 Gt/yr2). This shows the need for further effort to improve atmospheric mass estimates in this region of sparse in situ observations, in order to use GRACE observations to measure ice mass acceleration and related sea level change.

  1. Global precipitation estimates based on a technique for combining satellite-based estimates, rain gauge analysis, and NWP model precipitation information

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Rudolf, Bruno; Schneider, Udo; Keehn, Peter R.

    1995-01-01

    The 'satellite-gauge model' (SGM) technique is described for combining precipitation estimates from microwave satellite data, infrared satellite data, rain gauge analyses, and numerical weather prediction models into improved estimates of global precipitation. Throughout, monthly estimates on a 2.5 degrees x 2.5 degrees lat-long grid are employed. First, a multisatellite product is developed using a combination of low-orbit microwave and geosynchronous-orbit infrared data in the latitude range 40 degrees N - 40 degrees S (the adjusted geosynchronous precipitation index) and low-orbit microwave data alone at higher latitudes. Then the rain gauge analysis is brougth in, weighting each field by its inverse relative error variance to produce a nearly global, observationally based precipitation estimate. To produce a complete global estimate, the numerical model results are used to fill data voids in the combined satellite-gauge estimate. Our sequential approach to combining estimates allows a user to select the multisatellite estimate, the satellite-gauge estimate, or the full SGM estimate (observationally based estimates plus the model information). The primary limitation in the method is imperfections in the estimation of relative error for the individual fields. The SGM results for one year of data (July 1987 to June 1988) show important differences from the individual estimates, including model estimates as well as climatological estimates. In general, the SGM results are drier in the subtropics than the model and climatological results, reflecting the relatively dry microwave estimates that dominate the SGM in oceanic regions.

  2. EFFECT OF UNCERTAINTIES IN STELLAR MODEL PARAMETERS ON ESTIMATED MASSES AND RADII OF SINGLE STARS

    SciTech Connect

    Basu, Sarbani; Verner, Graham A.; Chaplin, William J.; Elsworth, Yvonne E-mail: gav@bison.ph.bham.ac.uk E-mail: y.p.elsworth@bham.ac.uk

    2012-02-10

    Accurate and precise values of radii and masses of stars are needed to correctly estimate properties of extrasolar planets. We examine the effect of uncertainties in stellar model parameters on estimates of the masses, radii, and average densities of solar-type stars. We find that in the absence of seismic data on solar-like oscillations, stellar masses can be determined to a greater accuracy than either stellar radii or densities; but to get reasonably accurate results the effective temperature, log g, and metallicity must be measured to high precision. When seismic data are available, stellar density is the most well-determined property, followed by radius, with mass the least well-determined property. Uncertainties in stellar convection, quantified in terms of uncertainties in the value of the mixing length parameter, cause the most significant errors in the estimates of stellar properties.

  3. Parameter estimation and control for a neural mass model based on the unscented Kalman filter

    NASA Astrophysics Data System (ADS)

    Liu, Xian; Gao, Qing

    2013-10-01

    Recent progress in Kalman filters to estimate states and parameters in nonlinear systems has provided the possibility of applying such approaches to neural systems. We here apply the nonlinear method of unscented Kalman filters (UKFs) to observe states and estimate parameters in a neural mass model that can simulate distinct rhythms in electroencephalography (EEG) including dynamical evolution during epilepsy seizures. We demonstrate the efficiency of the UKF in estimating states and parameters. We also develop an UKF-based control strategy to modulate the dynamics of the neural mass model. In this strategy the UKF plays the role of observing states, and the control law is constructed via the estimated states. We demonstrate the feasibility of using such a strategy to suppress epileptiform spikes in the neural mass model.

  4. A New Black Hole Mass Estimate for Obscured Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Minezaki, Takeo; Matsushita, Kyoko

    2015-04-01

    We propose a new method for estimating the mass of a supermassive black hole, applicable to obscured active galactic nuclei (AGNs). This method estimates the black hole mass using the width of the narrow core of the neutral FeKα emission line in X-rays and the distance of its emitting region from the black hole based on the isotropic luminosity indicator via the luminosity scaling relation. Assuming the virial relation between the locations and the velocity widths of the neutral FeKα line core and the broad Hβ emission line, the luminosity scaling relation of the neutral FeKα line core emitting region is estimated. We find that the velocity width of the neutral FeKα line core falls between that of the broad Balmer emission lines and the corresponding value at the dust reverberation radius for most of the target AGNs. The black hole mass {{M}BH,FeKα } estimated with this method is then compared with other black hole mass estimates, such as the broad emission-line reverberation mass {{M}BH,rev} for type 1 AGNs, the mass {{M}BH,{{H2}O}} based on the H2O maser, and the single-epoch mass estimate {{M}BH,pol} based on the polarized broad Balmer lines for type 2 AGNs. We find that {{M}BH,FeKα } is consistent with {{M}BH,rev} and {{M}BH,pol}, and find that {{M}BH,FeKα } correlates well with {{M}BH,{{H2}O}}. These results suggest that {{M}BH,FeKα } is a potential indicator of the black hole mass for obscured AGNs. In contrast, {{M}BH,FeKα } is systematically larger than {{M}BH,{{H2}O}} by about a factor of 5, and the possible origins are discussed.

  5. Estimating global carbon uptake by lichens and bryophytes with a process-based model

    NASA Astrophysics Data System (ADS)

    Porada, P.; Weber, B.; Elbert, W.; Pöschl, U.; Kleidon, A.

    2013-11-01

    Lichens and bryophytes are abundant globally and they may even form the dominant autotrophs in (sub)polar ecosystems, in deserts and at high altitudes. Moreover, they can be found in large amounts as epiphytes in old-growth forests. Here, we present the first process-based model which estimates the net carbon uptake by these organisms at the global scale, thus assessing their significance for biogeochemical cycles. The model uses gridded climate data and key properties of the habitat (e.g. disturbance intervals) to predict processes which control net carbon uptake, namely photosynthesis, respiration, water uptake and evaporation. It relies on equations used in many dynamical vegetation models, which are combined with concepts specific to lichens and bryophytes, such as poikilohydry or the effect of water content on CO2 diffusivity. To incorporate the great functional variation of lichens and bryophytes at the global scale, the model parameters are characterised by broad ranges of possible values instead of a single, globally uniform value. The predicted terrestrial net uptake of 0.34 to 3.3 Gt yr-1 of carbon and global patterns of productivity are in accordance with empirically-derived estimates. Considering that the assimilated carbon can be invested in processes such as weathering or nitrogen fixation, lichens and bryophytes may play a significant role in biogeochemical cycles.

  6. Estimating global carbon uptake by lichens and bryophytes with a process-based model

    NASA Astrophysics Data System (ADS)

    Porada, P.; Weber, B.; Elbert, W.; Pöschl, U.; Kleidon, A.

    2013-02-01

    Lichens and bryophytes are abundant globally and they may even form the dominant autotrophs in (sub)polar ecosystems, in deserts and at high altitudes. Moreover, they can be found in large amounts as epiphytes in old-growth forests. Here, we present the first process-based model which estimates the net carbon uptake by these organisms at the global scale, thus assessing their significance for biogeochemical cycles. The model uses gridded climate data and key properties of the habitat (e.g. disturbance intervals) to predict processes which control net carbon uptake, namely photosynthesis, respiration, water uptake and evaporation. It relies on equations used in many dynamical vegetation models, which are combined with concepts specific to lichens and bryophytes, such as poikilohydry or the effect of water content on CO2 diffusivity. To incorporate the great functional variation of lichens and bryophytes at the global scale, the model parameters are characterised by broad ranges of possible values instead of a single, globally uniform value. The predicted terrestrial net carbon uptake of 0.34 to 3.3 (Gt C) yr-1 and global patterns of productivity are in accordance with empirically-derived estimates. Considering that the assimilated carbon can be invested in processes such as weathering or nitrogen fixation, lichens and bryophytes may play a significant role in biogeochemical cycles.

  7. Internally Consistent MODIS Estimate of Aerosol Clear-Sky Radiative Effect Over the Global Oceans

    NASA Technical Reports Server (NTRS)

    Remer, Lorraine A.; Kaufman, Yoram J.

    2004-01-01

    Modern satellite remote sensing, and in particular the MODerate resolution Imaging Spectroradiometer (MODIS), offers a measurement-based pathway to estimate global aerosol radiative effects and aerosol radiative forcing. Over the Oceans, MODIS retrieves the total aerosol optical thickness, but also reports which combination of the 9 different aerosol models was used to obtain the retrieval. Each of the 9 models is characterized by a size distribution and complex refractive index, which through Mie calculations correspond to a unique set of single scattering albedo, assymetry parameter and spectral extinction for each model. The combination of these sets of optical parameters weighted by the optical thickness attributed to each model in the retrieval produces the best fit to the observed radiances at the top of the atmosphere. Thus the MODIS Ocean aerosol retrieval provides us with (1) An observed distribution of global aerosol loading, and (2) An internally-consistent, observed, distribution of aerosol optical models that when used in combination will best represent the radiances at the top of the atmosphere. We use these two observed global distributions to initialize the column climate model by Chou and Suarez to calculate the aerosol radiative effect at top of the atmosphere and the radiative efficiency of the aerosols over the global oceans. We apply the analysis to 3 years of MODIS retrievals from the Terra satellite and produce global and regional, seasonally varying, estimates of aerosol radiative effect over the clear-sky oceans.

  8. A new method to estimate average hourly global solar radiation on the horizontal surface

    NASA Astrophysics Data System (ADS)

    Pandey, Pramod K.; Soupir, Michelle L.

    2012-10-01

    A new model, Global Solar Radiation on Horizontal Surface (GSRHS), was developed to estimate the average hourly global solar radiation on the horizontal surfaces (Gh). The GSRHS model uses the transmission function (Tf,ij), which was developed to control hourly global solar radiation, for predicting solar radiation. The inputs of the model were: hour of day, day (Julian) of year, optimized parameter values, solar constant (H0), latitude, and longitude of the location of interest. The parameter values used in the model were optimized at a location (Albuquerque, NM), and these values were applied into the model for predicting average hourly global solar radiations at four different locations (Austin, TX; El Paso, TX; Desert Rock, NV; Seattle, WA) of the United States. The model performance was assessed using correlation coefficient (r), Mean Absolute Bias Error (MABE), Root Mean Square Error (RMSE), and coefficient of determinations (R2). The sensitivities of parameter to prediction were estimated. Results show that the model performed very well. The correlation coefficients (r) range from 0.96 to 0.99, while coefficients of determination (R2) range from 0.92 to 0.98. For daily and monthly prediction, error percentages (i.e. MABE and RMSE) were less than 20%. The approach we proposed here can be potentially useful for predicting average hourly global solar radiation on the horizontal surface for different locations, with the use of readily available data (i.e. latitude and longitude of the location) as inputs.

  9. Estimating the global terrestrial hydrologic cycle through modeling, remote sensing, and data assimilation

    NASA Astrophysics Data System (ADS)

    Pan, Ming; Troy, Tara; Sahoo, Alok; Sheffield, Justin; Wood, Eric

    2010-05-01

    Documentation of the water cycle and its evolution over time is a primary scientific goal of the Global Energy and Water Cycle Experiment (GEWEX) and fundamental to assessing global change impacts. In developed countries, observation systems that include in-situ, remote sensing and modeled data can provide long-term, consistent and generally high quality datasets of water cycle variables. The export of these technologies to less developed regions has been rare, but it is these regions where information on water availability and change is probably most needed in the face of regional environmental change due to climate, land use and water management. In these data sparse regions, in situ data alone are insufficient to develop a comprehensive picture of how the water cycle is changing, and strategies that merge in-situ, model and satellite observations within a framework that results in consistent water cycle records is essential. Such an approach is envisaged by the Global Earth Observing System of Systems (GOESS), but has yet to be applied. The goal of this study is to quantify the variation and changes in the global water cycle over the past 50 years. We evaluate the global water cycle using a variety of independent large-scale datasets of hydrologic variables that are used to bridge the gap between sparse in-situ observations, including remote-sensing based retrievals, observation-forced hydrologic modeling, and weather model reanalyses. A data assimilation framework that blends these disparate sources of information together in a consistent fashion with attention to budget closure is applied to make best estimates of the global water cycle and its variation. The framework consists of a constrained Kalman filter applied to the water budget equation. With imperfect estimates of the water budget components, the equation additionally has an error residual term that is redistributed across the budget components using error statistics, which are estimated from the

  10. Estimation of Croplands in West Africa using Global Land Cover and Land Use Datasets: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; de Beurs, K.

    2013-12-01

    Africa is vulnerable to the effects of global climate change resulting in reduced agricultural production and worsening food security. Studies show that Africa has the lowest cereal yield compared to other regions of the world. The situation is particularly dire in East, Central and West Africa. Despite their low cereal yield, the population of East, Central and West Africa has doubled between 1980 and 2007. Furthermore, West Africa has a history of severe and long droughts which have occasionally caused widespread famine. To understand how global climate change and land cover change have impacted crop production (yield) it is important to estimate croplands in the region. The objective of this study is to compare ten publicly available land cover and land use datasets, covering different time periods, to estimate croplands in West Africa. The land cover and land use data sets used cover the period from early 1990s to 2010. Preliminary results show a high variability in cropland estimates. For example, in Benin, the estimated cropland area varies from 2.5 to 21% of the total area, while it varies from 3 to 8% in Niger. Datasets with a finer resolution (≤ 1,000 m) have consistently estimated comparable cropland areas across all countries. Several categorical verification statistics such as probability of detection (POD), false alarm ratio (FAR) and critical success index are also used to analyze the correspondence between estimated and observed cropland pixels at the scales of 1 Km and 10 Km.

  11. Improving the estimation of terrestrial gross primary productivity by downscaling global sun-induced chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Cescatti, A.; Duveiller, G.

    2015-12-01

    The synoptic nature of satellite remote sensing makes this technique a key tool to contribute to estimating the amount of Carbon fixed by vegetation at global scale. From the various types of information that can be derived from space, the recent capacity to create global datasets of sun-induced chlorophyll fluorescence (SIF) may prove to be a game-changer. SIF is a signal emitted by the photosynthetic machinery itself that, under the illumination conditions in which it can be estimated by satellite, has been shown to be proportional to gross primary productivity (GPP). However, this relationship is dependent on vegetation types that are typically spatially mixed at the coarse spatial resolution of SIF datasets (at best 0.5°), which in turn is a consequence of the complexity of the SIF retrieval itself. This study demonstrates how 0.5° SIF derived from GOME-2 data can be downscaled to a more adequate spatial resolution of 0.05° by combining 3 explanatory biophysical variables derived from the MODIS sensor (NDVI, land surface temperature and evapotranspiration) under a semi-empirical light-use efficiency framework. The finer spatial resolution results in a cleaner signal when aggregating it per land cover type. The signal is also better correlated in time with GPP estimated from flux towers, reaching the same level of performance than global GPP products calibrated on such flux towers and driven by meteorological and remote sensing variables (other than SIF). Establishing linear relationships between SIF and flux-tower GPP at vegetation type level allows to estimate values of global terrestrial vegetation gross productivity that have different magnitude but similar temporal patterns as other GPP products. Based on downscaled SIF, the mean global GPP values over the period 2007 to 2013 are (for deciduous broadleaf and mixed forests) 13.7, (for evergreen needleleaf forests) 2.5, (for grasslands) 12.5 and (savannahs and woody savannas) 36.8 Pg of Carbon per year.

  12. Understanding the Role of Wind in Reducing the Surface Mass Balance Estimates over East Antarctica

    NASA Astrophysics Data System (ADS)

    Das, I.; Scambos, T. A.; Koenig, L.; Creyts, T. T.; Bell, R. E.; van den Broeke, M. R.; Lenaerts, J.; Paden, J. D.

    2014-12-01

    Accurate quantification of surface snow-accumulation over Antarctica is important for mass balance estimates and climate studies based on ice core records. An improved estimate of surface mass balance must include the significant role near-surface wind plays in the sublimation and redistribution of snow across Antarctica. We have developed an empirical model based on airborne radar and lidar observations, and modeled surface mass balance and wind fields to produce a continent-wide prediction of wind-scour zones over Antarctica. These zones have zero to negative surface mass balance, are located over locally steep ice sheet areas (>0.002) and controlled by bedrock topography. The near-surface winds accelerate over these zones, eroding and sublimating the surface snow. This scouring results in numerous localized regions (≤ 200 km2) with reduced surface accumulation. Each year, tens of gigatons of snow on the Antarctic ice sheet are ablated by persistent near-surface katabatic winds over these wind-scour zones. Large uncertainties remain in the surface mass balance estimates over East Antarctica as climate models do not adequately represent the small-scale physical processes that lead to mass loss through sublimation or redistribution over the wind-scour zones. In this study, we integrate Operation IceBridge's snow radar over the Recovery Ice Stream with a series of ice core dielectric and depth-density profiles for improved surface mass balance estimates that reflect the mass loss over the wind-scour zones. Accurate surface mass balance estimates from snow radars require spatially variable depth-density profiles. Using an ensemble of firn cores, MODIS-derived surface snow grain size, modeled accumulation rates and surface temperatures from RACMO2, we assemble spatially variable depth-density profiles and use our mapping of snow density variations to estimate layer mass and net accumulation rates from snow radar layer data. Our study improves the quantification of

  13. Toward a Quantitative Estimate of Future Heat Wave Mortality under Global Climate Change

    PubMed Central

    Peng, Roger D.; Bobb, Jennifer F.; Tebaldi, Claudia; McDaniel, Larry; Bell, Michelle L.; Dominici, Francesca

    2011-01-01

    Background Climate change is anticipated to affect human health by changing the distribution of known risk factors. Heat waves have had debilitating effects on human mortality, and global climate models predict an increase in the frequency and severity of heat waves. The extent to which climate change will harm human health through changes in the distribution of heat waves and the sources of uncertainty in estimating these effects have not been studied extensively. Objectives We estimated the future excess mortality attributable to heat waves under global climate change for a major U.S. city. Methods We used a database comprising daily data from 1987 through 2005 on mortality from all nonaccidental causes, ambient levels of particulate matter and ozone, temperature, and dew point temperature for the city of Chicago, Illinois. We estimated the associations between heat waves and mortality in Chicago using Poisson regression models. Results Under three different climate change scenarios for 2081–2100 and in the absence of adaptation, the city of Chicago could experience between 166 and 2,217 excess deaths per year attributable to heat waves, based on estimates from seven global climate models. We noted considerable variability in the projections of annual heat wave mortality; the largest source of variation was the choice of climate model. Conclusions The impact of future heat waves on human health will likely be profound, and significant gains can be expected by lowering future carbon dioxide emissions. PMID:21193384

  14. Dynamical Estimate of Post-main-sequence Stellar Masses in 47 Tucanae

    NASA Astrophysics Data System (ADS)

    Parada, Javiera; Richer, Harvey; Heyl, Jeremy; Kalirai, Jason; Goldsbury, Ryan

    2016-07-01

    We use the effects of mass segregation on the radial distribution of different stellar populations in the core of 47 Tucanae to find estimates for the masses of stars at different post-main-sequence evolutionary stages. We take samples of main-sequence (MS) stars from the core of 47 Tucanae, at different magnitudes (i.e., different masses), and use the effects of this dynamical process to develop a relation between the radial distance (RD) at which the cumulative distribution reaches the 20th and 50th percentile and stellar mass. From these relations we estimate the masses of different post-MS populations. We find that mass remains constant for stars going through the evolutionary stages from the upper MS up to the horizontal branch (HB). By comparing RDs of the HB stars with stars of lower masses, we can exclude a mass loss greater than 0.09 {M}ȯ during the red giant branch (RGB) stage at nearly the 3σ level. The slightly higher mass estimates for the asymptotic giant branch (AGB) are consistent with the AGB having evolved from somewhat more massive stars. The AGB also exhibits evidence of contamination by more massive stars, possibly blue straggler stars (BSSs), going through the RGB phase. We do not include the BSSs in this paper due to the complexity of these objects; instead, the complete analysis of this population is left for a companion paper. The process to estimate the masses described in this paper is exclusive to the core of 47 Tuc.

  15. Has Natural Variability Masked the Expected Increase in Antarctic Surface Mass Balance with Global Warming?

    NASA Astrophysics Data System (ADS)

    Previdi, Michael; Polvani, Lorenzo M.

    2016-04-01

    One of the expected and rather paradoxical consequences of anthropogenic global warming is an increase in Antarctic surface mass balance (or net snow accumulation), as robustly simulated by both global and regional climate models. This surface mass balance (SMB) increase occurs because the higher moisture content of a warmer atmosphere leads to increases in precipitation, with this precipitation falling in the form of snow over Antarctica. Despite these robust model projections, however, observations indicate that there has been no significant change in Antarctic SMB during the past several decades. Here, we show that this apparent discrepancy between models and observations can be explained by the fact that the anthropogenic climate change signal is still relatively 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 in a statistical sense as a result of large natural SMB variability on interannual-to-multidecadal timescales. However, our analysis reveals that if the world continues to follow the present trajectory of greenhouse gas emissions, the anthropogenic impact on Antarctic SMB will emerge from natural variability by the middle of the current century. With this, SMB increases over Antarctica will begin to mitigate global sea-level rise, partially offsetting the effects of dynamic ice loss.

  16. Estimating a Global Hydrological Carrying Capacity Using GRACE Observed Water Stress

    NASA Astrophysics Data System (ADS)

    An, K.; Reager, J. T.; Famiglietti, J. S.

    2013-12-01

    Global population is expected to reach 9 billion people by the year 2050, causing increased demands for water and potential threats to human security. This study attempts to frame the overpopulation problem through a hydrological resources lens by hypothesizing that observed groundwater trends should be directly attributed to human water consumption. This study analyzes the relationships between available blue water, population, and cropland area on a global scale. Using satellite data from NASA's Gravity Recovery and Climate Experiment (GRACE) along with land surface model data from the Global Land Data Assimilation System (GLDAS), a global groundwater depletion trend is isolated, the validity of which has been verified in many regional studies. By using the inherent distributions of these relationships, we estimate the regional populations that have exceeded their local hydrological carrying capacity. Globally, these populations sum to ~3.5 billion people that are living in presently water-stressed or potentially water-scarce regions, and we estimate total cropland is exceeding a sustainable threshold by about 80 million km^2. Key study areas such as the North China Plain, northwest India, and Mexico City were qualitatively chosen for further analysis of regional water resources and policies, based on our distributions of water stress. These case studies are used to verify the groundwater level changes seen in the GRACE trend . Tfor the many populous, arid regions of the world that have already begun to experience the strains of high water demand.he many populous, arid regions of the world have already begun to experience the strains of high water demand. It will take a global cooperative effort of improving domestic and agricultural use efficiency, and summoning a political will to prioritize environmental issues to adapt to a thirstier planet. Global Groundwater Depletion Trend (Mar 2003-Dec 2011)

  17. Estimating Global “Blue Carbon” Emissions from Conversion and Degradation of Vegetated Coastal Ecosystems

    PubMed Central

    Murray, Brian C.; Crooks, Stephen; Jenkins, W. Aaron; Sifleet, Samantha; Craft, Christopher; Fourqurean, James W.; Kauffman, J. Boone; Marbà, Núria; Megonigal, Patrick; Pidgeon, Emily; Herr, Dorothee; Gordon, David; Baldera, Alexis

    2012-01-01

    Recent attention has focused on the high rates of annual carbon sequestration in vegetated coastal ecosystems—marshes, mangroves, and seagrasses—that may be lost with habitat destruction (‘conversion’). Relatively unappreciated, however, is that conversion of these coastal ecosystems also impacts very large pools of previously-sequestered carbon. Residing mostly in sediments, this ‘blue carbon’ can be released to the atmosphere when these ecosystems are converted or degraded. Here we provide the first global estimates of this impact and evaluate its economic implications. Combining the best available data on global area, land-use conversion rates, and near-surface carbon stocks in each of the three ecosystems, using an uncertainty-propagation approach, we estimate that 0.15–1.02 Pg (billion tons) of carbon dioxide are being released annually, several times higher than previous estimates that account only for lost sequestration. These emissions are equivalent to 3–19% of those from deforestation globally, and result in economic damages of $US 6–42 billion annually. The largest sources of uncertainty in these estimates stems from limited certitude in global area and rates of land-use conversion, but research is also needed on the fates of ecosystem carbon upon conversion. Currently, carbon emissions from the conversion of vegetated coastal ecosystems are not included in emissions accounting or carbon market protocols, but this analysis suggests they may be disproportionally important to both. Although the relevant science supporting these initial estimates will need to be refined in coming years, it is clear that policies encouraging the sustainable management of coastal ecosystems could significantly reduce carbon emissions from the land-use sector, in addition to sustaining the well-recognized ecosystem services of coastal habitats. PMID:22962585

  18. Global lightning NOx production estimated by an assimilation of multiple satellite datasets

    NASA Astrophysics Data System (ADS)

    Miyazaki, K.; Eskes, H. J.; Sudo, K.; Zhang, C.

    2013-11-01

    The global source of lightning-produced NOx (LNOx) is estimated by assimilating observations of NO2, O3, HNO3, and CO measured by multiple satellite measurements. Included are observations from the Ozone Monitoring Instrument (OMI), Microwave Limb Sounder (MLS), Tropospheric Emission Spectrometer (TES), and Measurements of Pollution in the Troposphere (MOPITT) instruments. The assimilation of multiple chemical datasets with different vertical sensitivity profiles provides comprehensive constraints on the global LNOx source while improving the representations of the entire chemical system affecting atmospheric NOx, including surface emissions and inflows from the stratosphere. The annual global LNOx source amount and NO production efficiency are estimated at 6.3 Tg N yr-1 and 350 mol NO flash-1, respectively. Sensitivity studies with perturbed satellite datasets, model and data assimilation settings leads to an error estimate of about 1.4 Tg N yr-1 on this global LNOx source. These estimates are significantly different from those derived from NO2 observations alone, which may lead to an overestimate of the source adjustment. The total LNOx source is predominantly corrected by the assimilation of OMI NO2 observations, while TES and MLS observations add important constraints on the vertical source profile. The results indicate that the widely used lightning parameterization based on the C-shape assumption underestimates the source in the upper troposphere and overestimates the peak source height by up to about 1 km over land and the tropical western Pacific. Adjustments are larger over ocean than over land, suggesting that the cloud height dependence is too weak over the ocean in the Price and Rind (1992) approach. The significantly improved agreement between the analysed ozone fields and independent observations gives confidence in the performance of the LNOx source estimation.

  19. A general model for estimation of daily global solar radiation using air temperatures and site geographic parameters in Southwest China

    NASA Astrophysics Data System (ADS)

    Li, Mao-Fen; Fan, Li; Liu, Hong-Bin; Guo, Peng-Tao; Wu, Wei

    2013-01-01

    Estimation of daily global solar radiation (Rs) from routinely measured temperature data has been widely developed and used in many different areas of the world. However, many of them are site specific. It is assumed that a general model for estimating daily Rs using temperature variables and geographical parameters could be achieved within a climatic region. This paper made an attempt to develop a general model to estimate daily Rs using routinely measured temperature data (maximum (Tmax, °C) and minimum (Tmin, °C) temperatures) and site geographical parameters (latitude (La, °N), longitude (Ld, °E) and altitude (Alt, m)) for Guizhou and Sichuan basin of southwest China, which was classified into the hot summer and cold winter climate zone. Comparison analysis was carried out through statistics indicators such as root mean squared error of percentage (RMSE%), modeling efficiency (ME), coefficient of residual mass (CRM) and mean bias error (MBE). Site-dependent daily Rs estimating models were calibrated and validated using long-term observed weather data. A general formula was then obtained from site geographical parameters and the better fit site-dependent models with mean RMSE% of 38.68%, mean MBE of 0.381 MJ m-2 d-1, mean CRM of 0.04 and mean ME value of 0.713.

  20. The global chemical properties of high-mass star forming clumps at different evolutionary stages

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Jun; Zhou, Jian-Jun; Esimbek, Jarken; He, Yu-Xin; Li, Da-Lei; Tang, Xin-Di; Ji, Wei-Guang; Yuan, Ye; Guo, Wei-Hua

    2016-06-01

    A total of 197 relatively isolated high-mass star-forming clumps were selected from the Millimeter Astronomy Legacy Team 90 GHz (MALT90) survey data and their global chemical evolution investigated using four molecular lines, N2H+ (1--0), HCO+ (1--0), HCN (1-0), and HNC (1-0). The results suggest that the global averaged integrated intensity ratios I(HCO+)/I(HNC), I(HCN)/I(HNC), I(N2H+)/I(HCO+), and I(N2H+)/ I(HCN) are promising tracers for evolution of high-mass star-forming clumps. The global averaged column densities and abundances of N2H+, HCO+, HCN, and HNC increase as clumps evolve. The global averaged abundance ratios X(HCN)/X(HNC) could be used to trace evolution of high-mass star forming clumps, X(HCO+)/X(HNC) is more suitable for distinguishing high-mass star-forming clumps in prestellar (stage A) from those in protostellar (stage B) and HII/PDR region (stage C). These results suggest that the global averaged integrated intensity ratios between HCN (1-0), HNC (1-0), HCO+ (1--0) and N2H+ (1--0) are more suitable for tracing the evolution of high-mass star forming clumps. We also studied the chemical properties of the target high-mass star-forming clumps in each spiral arm of the Galaxy, and got results very different from those above. This is probably due to the relatively small sample in each spiral arm. For high-mass star-forming clumps in Sagittarius arm and Norma-Outer arm, comparing two groups located on one arm with different Galactocentric distances, the clumps near the Galactic Center appear to be younger than those far from the Galactic center, which may be due to more dense gas concentrated near the Galactic Center, and hence more massive stars being formed there.

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

    NASA Technical Reports Server (NTRS)

    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

  2. Estimation of submarine mass failure probability from a sequence of deposits with age dates

    USGS Publications Warehouse

    Geist, Eric L.; Chaytor, Jason D.; Parsons, Thomas E.; ten Brink, Uri S.

    2013-01-01

    The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from renewal process theory and Monte Carlo methods. The estimated mean return time from these methods, unlike estimates from a simple arithmetic mean of the center age dates and standard likelihood methods, includes the effects of age-dating uncertainty and of open time intervals before the first and after the last event. The likelihood techniques are evaluated using Akaike’s Information Criterion (AIC) and Akaike’s Bayesian Information Criterion (ABIC) to select the optimal model. The techniques are applied to mass transport deposits recorded in two Integrated Ocean Drilling Program (IODP) drill sites located in the Ursa Basin, northern Gulf of Mexico. Dates of the deposits were constrained by regional bio- and magnetostratigraphy from a previous study. Results of the analysis indicate that submarine mass failures in this location occur primarily according to a Poisson process in which failures are independent and return times follow an exponential distribution. However, some of the model results suggest that submarine mass failures may occur quasiperiodically at one of the sites (U1324). The suite of techniques described in this study provides quantitative probability estimates of submarine mass failure occurrence, for any number of deposits and age uncertainty distributions.

  3. Estimating the dark matter halo mass of our Milky Way using dynamical tracers

    NASA Astrophysics Data System (ADS)

    Wang, Wenting; Han, Jiaxin; Cooper, Andrew P.; Cole, Shaun; Frenk, Carlos; Lowing, Ben

    2015-10-01

    The mass of the dark matter halo of the Milky Way can be estimated by fitting analytical models to the phase-space distribution of dynamical tracers. We test this approach using realistic mock stellar haloes constructed from the Aquarius N-body simulations of dark matter haloes in the Λ cold dark matter cosmology. We extend the standard treatment to include a Navarro-Frenk-White potential and use a maximum likelihood method to recover the parameters describing the simulated haloes from the positions and velocities of their mock halo stars. We find that the estimate of halo mass is highly correlated with the estimate of halo concentration. The best-fitting halo masses within the virial radius, R200, are biased, ranging from a 40 per cent underestimate to a 5 per cent overestimate in the best case (when the tangential velocities of the tracers are included). There are several sources of bias. Deviations from dynamical equilibrium can potentially cause significant bias; deviations from spherical symmetry are relatively less important. Fits to stars at different galactocentric radii can give different mass estimates. By contrast, the model gives good constraints on the mass within the half-mass radius of tracers even when restricted to tracers within 60 kpc. The recovered velocity anisotropies of tracers, β, are biased systematically, but this does not affect other parameters if tangential velocity data are used as constraints.

  4. Accuracy of core mass estimates in simulated observations of dust emission

    NASA Astrophysics Data System (ADS)

    Malinen, J.; Juvela, M.; Collins, D. C.; Lunttila, T.; Padoan, P.

    2011-06-01

    Aims: We study the reliability of the mass estimates obtained for molecular cloud cores using sub-millimetre and infrared dust emission. Methods: We use magnetohydrodynamic simulations and radiative transfer to produce synthetic observations with spatial resolution and noise levels typical of Herschel surveys. We estimate dust colour temperatures using different pairs of intensities, calculate column densities with opacity at one wavelength, and compare the estimated masses with the true values. We compare these results to the case when all five Herschel wavelengths are available. We investigate the effects of spatial variations of dust properties and the influence of embedded heating sources. Results: Wrong assumptions of dust opacity and its spectral index β can cause significant systematic errors in mass estimates. These are mainly multiplicative and leave the slope of the mass spectrum intact, unless cores with very high optical depth are included. Temperature variations bias the colour temperature estimates and, in quiescent cores with optical depths higher than for normal stable cores, masses can be underestimated by up to one order of magnitude. When heated by internal radiation sources, the dust in the core centre becomes visible and the observations recover the true mass spectra. Conclusions: The shape, although not the position, of the mass spectrum is reliable against observational errors and biases introduced in the analysis. This changes only if the cores have optical depths much higher than expected for basic hydrostatic equilibrium conditions. Observations underestimate the value of β whenever there are temperature variations along the line of sight. A bias can also be observed when the true β varies with wavelength. Internal heating sources produce an inverse correlation between colour temperature and β that may be difficult to separate from any intrinsic β(T) relation of the dust grains. This suggests caution when interpreting the observed

  5. Demonstration of precise estimation of polar motion parameters with the global positioning system: Initial results

    NASA Technical Reports Server (NTRS)

    Lichten, S. M.

    1991-01-01

    Data from the Global Positioning System (GPS) were used to determine precise polar motion estimates. Conservatively calculated formal errors of the GPS least squares solution are approx. 10 cm. The GPS estimates agree with independently determined polar motion values from very long baseline interferometry (VLBI) at the 5 cm level. The data were obtained from a partial constellation of GPS satellites and from a sparse worldwide distribution of ground stations. The accuracy of the GPS estimates should continue to improve as more satellites and ground receivers become operational, and eventually a near real time GPS capability should be available. Because the GPS data are obtained and processed independently from the large radio antennas at the Deep Space Network (DSN), GPS estimation could provide very precise measurements of Earth orientation for calibration of deep space tracking data and could significantly relieve the ever growing burden on the DSN radio telescopes to provide Earth platform calibrations.

  6. The High-Mass End of the Black Hole Mass Function: Mass Estimates in Brightest Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Dalla Bontà, E.; Ferrarese, L.; Corsini, E. M.; Miralda-Escudé, J.; Coccato, L.; Sarzi, M.; Pizzella, A.; Beifiori, A.

    2009-01-01

    We present Hubble Space Telescope imaging and spectroscopic observations of three Brightest Cluster Galaxies, Abell 1836-BCG, Abell 2052-BCG, and Abell 3565-BCG, obtained with the Wide Field and Planetary Camera 2, the Advanced Camera for Surveys and the Space Telescope Imaging Spectrograph. The data provide detailed information on the structure and mass profile of the stellar component, the dust optical depth, and the spatial distribution and kinematics of the ionized gas within the innermost region of each galaxy. Dynamical models, which account for the observed stellar mass profile and include the contribution of a central supermassive black hole (SBH), are constructed to reproduce the kinematics derived from the Hα and [N II]λλ6548,6583 emission lines. Secure SBH detection with M • = 3.61+0.41 -0.50 × 109 M sun and M • = 1.34+0.21 -0.19 × 109 M sun, respectively, are obtained for Abell 1836-BCG and Abell 3565-BCG, which show regular rotation curves and strong central velocity gradients. In the case of Abell 2052-BCG, the lack of an orderly rotational motion prevents a secure determination, although an upper limit of M • lsim 4.60 × 109 M sun can be placed on the mass of the central SBH. These measurements represent an important step forward in the characterization of the high-mass end of the SBH mass function. Based on observations made with ESO telescopes at the La Silla Paranal Observatory under programme ID 279.B-5004(A).

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

    NASA Astrophysics Data System (ADS)

    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.

  8. VizieR Online Data Catalog: SDSS bulge, disk and total stellar mass estimates (Mendel+, 2014)

    NASA Astrophysics Data System (ADS)

    Mendel, J. T.; Simard, L.; Palmer, M.; Ellison, S. L.; Patton, D. R.

    2014-01-01

    We present a catalog of bulge, disk, and total stellar mass estimates for ~660000 galaxies in the Legacy area of the Sloan Digital Sky Survey Data (SDSS) Release 7. These masses are based on a homogeneous catalog of g- and r-band photometry described by Simard et al. (2011, Cat. J/ApJS/196/11), which we extend here with bulge+disk and Sersic profile photometric decompositions in the SDSS u, i, and z bands. We discuss the methodology used to derive stellar masses from these data via fitting to broadband spectral energy distributions (SEDs), and show that the typical statistical uncertainty on total, bulge, and disk stellar mass is ~0.15 dex. Despite relatively small formal uncertainties, we argue that SED modeling assumptions, including the choice of synthesis model, extinction law, initial mass function, and details of stellar evolution likely contribute an additional 60% systematic uncertainty in any mass estimate based on broadband SED fitting. We discuss several approaches for identifying genuine bulge+disk systems based on both their statistical likelihood and an analysis of their one-dimensional surface-brightness profiles, and include these metrics in the catalogs. Estimates of the total, bulge and disk stellar masses for both normal and dust-free models and their uncertainties are made publicly available here. (4 data files).

  9. Approaches to refining estimates of global burden and economics of dengue.

    PubMed

    Shepard, Donald S; Undurraga, Eduardo A; Betancourt-Cravioto, Miguel; Guzmán, María G; Halstead, Scott B; Harris, Eva; Mudin, Rose Nani; Murray, Kristy O; Tapia-Conyer, Roberto; Gubler, Duane J

    2014-11-01

    Dengue presents a formidable and growing global economic and disease burden, with around half the world's population estimated to be at risk of infection. There is wide variation and substantial uncertainty in current estimates of dengue disease burden and, consequently, on economic burden estimates. Dengue disease varies across time, geography and persons affected. Variations in the transmission of four different viruses and interactions among vector density and host's immune status, age, pre-existing medical conditions, all contribute to the disease's complexity. This systematic review aims to identify and examine estimates of dengue disease burden and costs, discuss major sources of uncertainty, and suggest next steps to improve estimates. Economic analysis of dengue is mainly concerned with costs of illness, particularly in estimating total episodes of symptomatic dengue. However, national dengue disease reporting systems show a great diversity in design and implementation, hindering accurate global estimates of dengue episodes and country comparisons. A combination of immediate, short-, and long-term strategies could substantially improve estimates of disease and, consequently, of economic burden of dengue. Suggestions for immediate implementation include refining analysis of currently available data to adjust reported episodes and expanding data collection in empirical studies, such as documenting the number of ambulatory visits before and after hospitalization and including breakdowns by age. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to evaluate the accuracy of reporting rates (by health sector, treatment, severity, etc.), and using covariates to extrapolate dengue incidence to locations with no or limited reporting. Long-term efforts aim at strengthening capacity to document dengue transmission using serological methods to systematically analyze and relate to epidemiologic data. As promising tools

  10. Approaches to Refining Estimates of Global Burden and Economics of Dengue

    PubMed Central

    Shepard, Donald S.; Undurraga, Eduardo A.; Betancourt-Cravioto, Miguel; Guzmán, María G.; Halstead, Scott B.; Harris, Eva; Mudin, Rose Nani; Murray, Kristy O.; Tapia-Conyer, Roberto; Gubler, Duane J.

    2014-01-01

    Dengue presents a formidable and growing global economic and disease burden, with around half the world's population estimated to be at risk of infection. There is wide variation and substantial uncertainty in current estimates of dengue disease burden and, consequently, on economic burden estimates. Dengue disease varies across time, geography and persons affected. Variations in the transmission of four different viruses and interactions among vector density and host's immune status, age, pre-existing medical conditions, all contribute to the disease's complexity. This systematic review aims to identify and examine estimates of dengue disease burden and costs, discuss major sources of uncertainty, and suggest next steps to improve estimates. Economic analysis of dengue is mainly concerned with costs of illness, particularly in estimating total episodes of symptomatic dengue. However, national dengue disease reporting systems show a great diversity in design and implementation, hindering accurate global estimates of dengue episodes and country comparisons. A combination of immediate, short-, and long-term strategies could substantially improve estimates of disease and, consequently, of economic burden of dengue. Suggestions for immediate implementation include refining analysis of currently available data to adjust reported episodes and expanding data collection in empirical studies, such as documenting the number of ambulatory visits before and after hospitalization and including breakdowns by age. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to evaluate the accuracy of reporting rates (by health sector, treatment, severity, etc.), and using covariates to extrapolate dengue incidence to locations with no or limited reporting. Long-term efforts aim at strengthening capacity to document dengue transmission using serological methods to systematically analyze and relate to epidemiologic data. As promising tools

  11. Development of Global Precipitation Estimation System Using Artificial Neural Network Models

    NASA Astrophysics Data System (ADS)

    Hsu, K. L.

    2015-12-01

    The PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Network) system, developed at UC Irvine, is one unique source to estimate global precipitation in near real-time using infrared and passive microwave information from Geosynchronous Earth Orbital (GEO) and Low Earth Orbital (LEO) satellites. The algorithm uses an Artificial Neural Network to extract cold cloud pixels and neighboring features from GEO-satellites' infrared images to generate rain rate. The precipitation estimates from the neural network are further adjusted by the PMW precipitation estimates produced using the data from LEO satellites. The operational PERSIANN system estimates global precipitation in near real-time. Data sources are also extended to the reconstruction of historical data for the past 30 years for hydroclimate studies. Continuing development of precipitation retrieval using artificial neural network models and advanced machine learning methods are ongoing. Studies including effective feature extraction from satellite multiple spectral imagery, integration of multiple satellite information, and merge of ground and satellite precipitation retrievals. Evaluation of PERSIANN precipitation and its application for catchment scale hydrologic simulation will be discussed.

  12. Reconciliation of excess 14C-constrained global CO2 piston velocity estimates

    NASA Astrophysics Data System (ADS)

    Naegler, Tobias

    2009-04-01

    Oceanic excess radiocarbon data is widely used as a constraint for air-sea gas exchange. However, recent estimates of the global mean piston velocity from Naegler et al., Krakauer et al., Sweeney et al. and Müller et al. differ substantially despite the fact that they all are based on excess radiocarbon data from the GLODAP data base. Here I show that these estimates of can be reconciled if first, the changing oceanic radiocarbon inventory due to net uptake of CO2 is taken into account; second, if realistic reconstructions of sea surface Δ14C are used and third, if is consistently reported with or without normalization to a Schmidt number of 660. These corrections applied, unnormalized estimates of from these studies range between 15.1 and 18.2cmh-1. However, none of these estimates can be regarded as the only correct value for . I thus propose to use the `average' of the corrected values of presented here (16.5+/-3.2cmh-1) as the best available estimate of the global mean unnormalized piston velocity , resulting in a gross ocean-to-atmosphere CO2 flux of 76 +/- 15PgCyr-1 for the mid-1990s.

  13. Assembling GHERG: Could "academic crowd-sourcing" address gaps in global health estimates?

    PubMed

    Rudan, Igor; Campbell, Harry; Marušić, Ana; Sridhar, Devi; Nair, Harish; Adeloye, Davies; Theodoratou, Evropi; Chan, Kit Yee

    2015-06-01

    In recent months, the World Health Organization (WHO), independent academic researchers, the Lancet and PLoS Medicine journals worked together to improve reporting of population health estimates. The new guidelines for accurate and transparent health estimates reporting (likely to be named GATHER), which are eagerly awaited, represent a helpful move that should benefit the field of global health metrics. Building on this progress and drawing from a tradition of Child Health Epidemiology Reference Group (CHERG)'s successful work model, we would like to propose a new initiative - "Global Health Epidemiology Reference Group" (GHERG). We see GHERG as an informal and entirely voluntary international collaboration of academic groups who are willing to contribute to improving disease burden estimates and respect the principles of the new guidelines - a form of "academic crowd-sourcing". The main focus of GHERG will be to identify the "gap areas" where not much information is available and/or where there is a lot of uncertainty present about the accuracy of the existing estimates. This approach should serve to complement the existing WHO and IHME estimates and to represent added value to both efforts. PMID:26445671

  14. Assembling GHERG: Could “academic crowd–sourcing” address gaps in global health estimates?

    PubMed Central

    Rudan, Igor; Campbell, Harry; Marušić, Ana; Sridhar, Devi; Nair, Harish; Adeloye, Davies; Theodoratou, Evropi; Chan, Kit Yee

    2015-01-01

    In recent months, the World Health Organization (WHO), independent academic researchers, the Lancet and PLoS Medicine journals worked together to improve reporting of population health estimates. The new guidelines for accurate and transparent health estimates reporting (likely to be named GATHER), which are eagerly awaited, represent a helpful move that should benefit the field of global health metrics. Building on this progress and drawing from a tradition of Child Health Epidemiology Reference Group (CHERG)’s successful work model, we would like to propose a new initiative – “Global Health Epidemiology Reference Group” (GHERG). We see GHERG as an informal and entirely voluntary international collaboration of academic groups who are willing to contribute to improving disease burden estimates and respect the principles of the new guidelines – a form of “academic crowd–sourcing”. The main focus of GHERG will be to identify the “gap areas” where not much information is available and/or where there is a lot of uncertainty present about the accuracy of the existing estimates. This approach should serve to complement the existing WHO and IHME estimates and to represent added value to both efforts. PMID:26445671

  15. Estimation of symmetric and asymmetric hourly global and diffuse radiation from daily values

    SciTech Connect

    Satyamurty, V.V.; Lahiri, P.K. )

    1992-01-01

    The validity of the correlations to estimate the hourly global and diffuse solar radiation components for an independent dataset of fourteen locations is examined in this article. The correlation for the diffuse component are found to be rather poor agreement with the data. An improved correlation for the diffuse component that includes a daily diffuse fraction as a parameter is developed. The influence of this improved correlation on estimating the beam radiation component is examined. A convenient form of describing asymmetry for these three components of solar radiation distribution is proposed and validated.

  16. Vector Observation-Aided/Attitude-Rate Estimation Using Global Positioning System Signals

    NASA Technical Reports Server (NTRS)

    Oshman, Yaakov; Markley, F. Landis

    1997-01-01

    A sequential filtering algorithm is presented for attitude and attitude-rate estimation from Global Positioning System (GPS) differential carrier phase measurements. A third-order, minimal-parameter method for solving the attitude matrix kinematic equation is used to parameterize the filter's state, which renders the resulting estimator computationally efficient. Borrowing from tracking theory concepts, the angular acceleration is modeled as an exponentially autocorrelated stochastic process, thus avoiding the use of the uncertain spacecraft dynamic model. The new formulation facilitates the use of aiding vector observations in a unified filtering algorithm, which can enhance the method's robustness and accuracy. Numerical examples are used to demonstrate the performance of the method.

  17. Estimation of aerosol mass scattering efficiencies under high mass loading: case study for the megacity of Shanghai, China.

    PubMed

    Cheng, Zhen; Jiang, Jingkun; Chen, Changhong; Gao, Jian; Wang, Shuxiao; Watson, John G; Wang, Hongli; Deng, Jianguo; Wang, Buying; Zhou, Min; Chow, Judith C; Pitchford, Marc L; Hao, Jiming

    2015-01-20

    Aerosol mass scattering efficiency (MSE), used for the scattering coefficient apportionment of aerosol species, is often studied under the condition of low aerosol mass loading in developed countries. Severe pollution episodes with high particle concentration frequently happened in eastern urban China in recent years. Based on synchronous measurement of aerosol physical, chemical, and optical properties at the megacity of Shanghai for two months during autumn 2012, we studied MSE characteristics at high aerosol mass loading. Their relationships with mass concentrations and size distributions were examined. It was found that MSE values from the original US IMPROVE algorithm could not represent the actual aerosol characteristics in eastern China. It results in an underestimation of the measured ambient scattering coefficient by 36%. MSE values in Shanghai were estimated to be 3.5 ± 0.55 m(2)/g for ammonia sulfate, 4.3 ± 0.63 m(2)/g for ammonia nitrate, and 4.5 ± 0.73 m(2)/g for organic matter, respectively. MSEs for three components increased rapidly with increasing mass concentration in low aerosol mass loading, then kept at a stable level after a threshold mass concentration of 12–24 μg/m(3). During severe pollution episodes, particle growth from an initial peak diameter of 200–300 nm to a peak diameter of 500–600 nm accounts for the rapid increase in MSEs at high aerosol mass loading, that is, particle diameter becomes closer to the wavelength of visible lights. This study provides insights of aerosol scattering properties at high aerosol concentrations and implies the necessity of MSE localization for extinction apportionment, especially for the polluted regions. PMID:25495050

  18. Understanding the Global Structure and Evolution of Coronal Mass Ejections in the Solar Wind

    NASA Technical Reports Server (NTRS)

    Riley, Pete

    2004-01-01

    This report summarizes the technical progress made during the first six months of the second year of the NASA Living with a Star program contract Understanding the global structure and evolution of coronal mass ejections in the solar wind, between NASA and Science Applications International Corporation, and covers the period November 18, 2003 - May 17,2004. Under this contract SAIC has conducted numerical and data analysis related to fundamental issues concerning the origin, intrinsic properties, global structure, and evolution of coronal mass ejections in the solar wind. During this working period we have focused on a quantitative assessment of 5 flux rope fitting techniques. In the following sections we summarize the main aspects of this work and our proposed investigation plan for the next reporting period. Thus far, our investigation has resulted in 6 refereed scientific publications and we have presented the results at a number of scientific meetings and workshops.

  19. Estimation of trapped mass by in-cylinder pressure resonance in HCCI engines

    NASA Astrophysics Data System (ADS)

    Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Bares, Pau

    2016-01-01

    High pressure gradients at homogeneous charge compression ignition (HCCI) engines heavily excite the pressure resonance. The pressure resonant frequency depends on speed of sound in the cylinder, and thus on the bulk gas temperature. Present paper profits this relation estimating the trapped mass inside the cylinder. In contrast to other estimation methods in the literature, the presented method is based on the trace of the in-cylinder pressure during the cycle; therefore, it permits a cycle-to-cycle mass estimation, and avoids errors associated with other assumptions, such as heat transfer during compression or initial temperature of the in-cylinder gases. The proposed strategy only needs the pressure signal, a volume estimation and a composition assumption to obtain several trapped mass estimates during one cycle. These estimates can be later combined for providing an error estimate of the measurement, with the assumption of negligible blow-by. The method is demonstrated in two HCCI engines of different size, showing good performance in steady operation and presenting great potential to control transient operation.

  20. REPRODUCING THE STELLAR MASS/HALO MASS RELATION IN SIMULATED {Lambda}CDM GALAXIES: THEORY VERSUS OBSERVATIONAL ESTIMATES

    SciTech Connect

    Munshi, Ferah; Governato, F.; Loebman, S.; Quinn, T.; Brooks, A. M.; Christensen, C.; Shen, S.; Moster, B.; Wadsley, J.

    2013-03-20

    We examine the present-day total stellar-to-halo mass (SHM) ratio as a function of halo mass for a new sample of simulated field galaxies using fully cosmological, {Lambda}CDM, high-resolution SPH + N-body simulations. These simulations include an explicit treatment of metal line cooling, dust and self-shielding, H{sub 2}-based star formation (SF), and supernova-driven gas outflows. The 18 simulated halos have masses ranging from a few times 10{sup 8} to nearly 10{sup 12} M{sub Sun }. At z = 0, our simulated galaxies have a baryon content and morphology typical of field galaxies. Over a stellar mass range of 2.2 Multiplication-Sign 10{sup 3}-4.5 Multiplication-Sign 10{sup 10} M{sub Sun} we find extremely good agreement between the SHM ratio in simulations and the present-day predictions from the statistical abundance matching technique presented in Moster et al. This improvement over past simulations is due to a number systematic factors, each decreasing the SHM ratios: (1) gas outflows that reduce the overall SF efficiency but allow for the formation of a cold gas component; (2) estimating the stellar masses of simulated galaxies using artificial observations and photometric techniques similar to those used in observations; and (3) accounting for a systematic, up to 30% overestimate in total halo masses in DM-only simulations, due to the neglect of baryon loss over cosmic times. Our analysis suggests that stellar mass estimates based on photometric magnitudes can underestimate the contribution of old stellar populations to the total stellar mass, leading to stellar mass errors of up to 50% for individual galaxies. These results highlight that implementing a realistic high density threshold for SF considerably reduces the overall SF efficiency due to more effective feedback. However, we show that in order to reduce the perceived tension between the SF efficiency in galaxy formation models and in real galaxies, it is very important to use proper techniques to

  1. Mangrove production and carbon sinks: A revision of global budget estimates

    USGS Publications Warehouse

    Bouillon, S.; Borges, A.V.; Castaneda-Moya, E.; Diele, K.; Dittmar, T.; Duke, N.C.; Kristensen, E.; Lee, S.-Y.; Marchand, C.; Middelburg, J.J.; Rivera-Monroy, V. H.; Smith, T. J., III; Twilley, R.R.

    2008-01-01

    Mangrove forests are highly productive but globally threatened coastal ecosystems, whose role in the carbon budget of the coastal zone has long been debated. Here we provide a comprehensive synthesis of the available data on carbon fluxes in mangrove ecosystems. A reassessment of global mangrove primary production from the literature results in a conservative estimate of ???-218 ?? 72 Tg C a-1. When using the best available estimates of various carbon sinks (organic carbon export, sediment burial, and mineralization), it appears that >50% of the carbon fixed by mangrove vegetation is unaccounted for. This unaccounted carbon sink is conservatively estimated at ??? 112 ?? 85 Tg C a-1, equivalent in magnitude to ??? 30-40% of the global riverine organic carbon input to the coastal zone. Our analysis suggests that mineralization is severely underestimated, and that the majority of carbon export from mangroves to adjacent waters occurs as dissolved inorganic carbon (DIC). CO2 efflux from sediments and creek waters and tidal export of DIC appear to be the major sinks. These processes are quantitatively comparable in magnitude to the unaccounted carbon sink in current budgets, but are not yet adequately constrained with the limited published data available so far. Copyright 2008 by the American Geophysical Union.

  2. Estimating the broadband longwave emissivity of global bare soil from the MODIS shortwave albedo product

    NASA Astrophysics Data System (ADS)

    Cheng, Jie; Liang, Shunlin

    2014-01-01

    A constant land surface longwave emissivity value, or very simple parameterization, has been adopted by current land surface models because of a current lack of reliable observations. Of all the various Earth surface types, bare soil has the highest variations in broadband emissivity (BBE). We propose here a new algorithm to estimate BBE in the 8-13.5 µm spectral range based on the Moderate Resolution Imaging Spectrometer (MODIS) albedo product for bare soil. This algorithm takes advantage of both Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) longwave emissivity and MODIS shortwave albedo products, as well as the established linear relationship between ASTER BBE and seven MODIS spectral albedos for bare soil. In order to mitigate step discontinuities in the global land surface BBE product, a transition zone was established and the BBE estimation method was also provided. Three linear formulae were derived for bare soil and transition zones, respectively. Given the accuracy of 0.01 for MODIS spectral albedo, the absolute accuracy of BBE retrieval is better than 0.017. The validation results obtained from the three field trials conducted in China and one field trial in western/southwestern U.S. indicated that the average difference between the estimated BBE and the measured BBE was 0.016. We have introduced a new strategy to generate global land surface BBE using MODIS data. This strategy was used to generate global 8 day 1 km land surface BBE products from 2000 through 2010.

  3. The method of tailored sensitivity kernels for GRACE mass change estimates

    NASA Astrophysics Data System (ADS)

    Groh, Andreas; Horwath, Martin

    2016-04-01

    To infer mass changes (such as mass changes of an ice sheet) from time series of GRACE spherical harmonic solutions, two basic approaches (with many variants) exist: The regional integration approach (or direct approach) is based on surface mass changes (equivalent water height, EWH) from GRACE and integrates those with specific integration kernels. The forward modeling approach (or mascon approach, or inverse approach) prescribes a finite set of mass change patterns and adjusts the amplitudes of those patterns (in a least squares sense) to the GRACE gravity field changes. The present study reviews the theoretical framework of both approaches. We recall that forward modeling approaches ultimately estimate mass changes by linear functionals of the gravity field changes. Therefore, they implicitly apply sensitivity kernels and may be considered as special realizations of the regional integration approach. We show examples for sensitivity kernels intrinsic to forward modeling approaches. We then propose to directly tailor sensitivity kernels (or in other words: mass change estimators) by a formal optimization procedure that minimizes the sum of propagated GRACE solution errors and leakage errors. This approach involves the incorporation of information on the structure of GRACE errors and the structure of those mass change signals that are most relevant for leakage errors. We discuss the realization of this method, as applied within the ESA "Antarctic Ice Sheet CCI (Climate Change Initiative)" project. Finally, results for the Antarctic Ice Sheet in terms of time series of mass changes of individual drainage basins and time series of gridded EWH changes are presented.

  4. Evaluation of the applicability of the Estimated State of the Global Ocean for Climate Research (ESTOC) data set

    NASA Astrophysics Data System (ADS)

    Osafune, S.; Masuda, S.; Sugiura, N.; Doi, T.

    2015-06-01

    A long-term data synthesis experiment was conducted for the period 1957-2011 using a modified quasi-global four-dimensional variational data assimilation system that was originally developed to improve the representation of the deep ocean, including a unique method for anomaly assimilation. The overall characteristics of the resulting ocean state estimate, which is dynamically consistent without any artificial sources or sinks for heat and salt, are evaluated in the Pacific Ocean. It is shown that the data set better represents the comprehensive ocean state: the mean state of the water mass distribution and volume transport and components of temporal variability from the sea surface to the bottom on interannual to multidecadal timescales. This suggests that the data set can be used to examine interactions between temporal variations throughout the entire depth range and is useful for understanding ocean physics and its role in the climate system.

  5. Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

    NASA Astrophysics Data System (ADS)

    Locatelli, R.; Bousquet, P.; Chevallier, F.; Fortems-Cheney, A.; Szopa, S.; Saunois, M.; Agusti-Panareda, A.; Bergmann, D.; Bian, H.; Cameron-Smith, P.; Chipperfield, M. P.; Gloor, E.; Houweling, S.; Kawa, S. R.; Krol, M.; Patra, P. K.; Prinn, R. G.; Rigby, M.; Saito, R.; Wilson, C.

    2013-10-01

    A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System) inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure) is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr-1 at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr-1 in North America to 7 Tg yr-1 in Boreal Eurasia (from 23 to 48%, respectively). At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly question the consistency of

  6. ANALYSIS OF SOIL VAPOR EXTRACTION DATA TO EVALUATE MASS-TRANSFER CONSTRAINTS AND ESTIMATE SOURCE-ZONE MASS FLUX

    PubMed Central

    Rohay, Virginia; Truex, Michael J.

    2013-01-01

    Methods are developed to use data collected during cyclic operation of soil vapor extraction (SVE) systems to help characterize the magnitudes and timescales of mass flux associated with vadose zone contaminant sources. Operational data collected at the Department of Energy’s Hanford site are used to illustrate the use of such data. An analysis was conducted of carbon tetrachloride vapor concentrations collected during and between SVE operations. The objective of the analysis was to evaluate changes in concentrations measured during periods of operation and non-operation of SVE, with a focus on quantifying temporal dynamics of the vadose zone contaminant mass flux, and associated source strength. Three mass-flux terms, representing mass flux during the initial period of a SVE cycle, during the asymptotic period of a cycle, and during the rebound period, were calculated and compared. It was shown that it is possible to use the data to estimate time frames for effective operation of an SVE system if a sufficient set of historical cyclic operational data exists. This information could then be used to help evaluate changes in SVE operations, including system closure. The mass-flux data would also be useful for risk assessments of the impact of vadose-zone sources on groundwater contamination or vapor intrusion. PMID:23516336

  7. Estimation of mass changes caused by vegetation using AMSR-E

    NASA Astrophysics Data System (ADS)

    Schnitzer, S.; Abelen, S.; Menzel, A.; Seitz, F.

    2012-04-01

    Vegetation is one of the most important compartments in the global ecosystem, influencing soil, water balance, atmosphere, and the climate in general. Even though this is a known fact, large areas of rain forest are still destroyed for wood production or by food industries increasing their agricultural areas for soy production and stock farming. But also wild fires devastate large amounts to vegetation. Therefore, it is essential to monitor the changes of vegetation globally. In our study we address the question how big the mass changes in vegetation are. We observe the following sources of changes: 1) wild fires, 2) clear cut and 3) seasonal variations of vegetation. For the first two items we consider only forest areas where the biggest mass variations are taking place. The third point takes the entire range of vegetation classes into account. In order to observe vegetation globally we use remote sensing data from the sensor AMSR-E (Advanced Microwave Scanning Radiometer - EOS) aboard of Nasa's Aqua satellite. This sensor provides data from 2002 until 2011. The data include information about the vegetation water content and are therefore ideal for our purpose. We validate our results with the help of additional databases listings, on e.g. large fire events, from literature as well as from in-situ data. The talk is concluded with a global map of hotspots of big vegetation mass changes and their triggers.

  8. Optimal estimation for global ground-level fine particulate matter concentrations

    NASA Astrophysics Data System (ADS)

    Donkelaar, Aaron; Martin, Randall V.; Spurr, Robert J. D.; Drury, Easan; Remer, Lorraine A.; Levy, Robert C.; Wang, Jun

    2013-06-01

    We develop an optimal estimation (OE) algorithm based on top-of-atmosphere reflectances observed by the MODIS satellite instrument to retrieve near-surface fine particulate matter (PM2.5). The GEOS-Chem chemical transport model is used to provide prior information for the Aerosol Optical Depth (AOD) retrieval and to relate total column AOD to PM2.5. We adjust the shape of the GEOS-Chem relative vertical extinction profiles by comparison with lidar retrievals from the CALIOP satellite instrument. Surface reflectance relationships used in the OE algorithm are indexed by land type. Error quantities needed for this OE algorithm are inferred by comparison with AOD observations taken by a worldwide network of sun photometers (AERONET) and extended globally based upon aerosol speciation and cross correlation for simulated values, and upon land type for observational values. Significant agreement in PM2.5 is found over North America for 2005 (slope = 0.89; r = 0.82; 1-σ error = 1 µg/m3 + 27%), with improved coverage and correlation relative to previous work for the same region and time period, although certain subregions, such as the San Joaquin Valley of California are better represented by previous estimates. Independently derived error estimates of the OE PM2.5 values at in situ locations over North America (of ±(2.5 µg/m3 + 31%) and Europe of ±(3.5 µg/m3 + 30%) are corroborated by comparison with in situ observations, although globally (error estimates of ±(3.0 µg/m3 + 35%), may be underestimated. Global population-weighted PM2.5 at 50% relative humidity is estimated as 27.8 µg/m3 at 0.1° × 0.1° resolution.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  11. A Simple Analytic Model for Estimating Mars Ascent Vehicle Mass and Performance

    NASA Technical Reports Server (NTRS)

    Woolley, Ryan C.

    2014-01-01

    The Mars Ascent Vehicle (MAV) is a crucial component in any sample return campaign. In this paper we present a universal model for a two-stage MAV along with the analytic equations and simple parametric relationships necessary to quickly estimate MAV mass and performance. Ascent trajectories can be modeled as two-burn transfers from the surface with appropriate loss estimations for finite burns, steering, and drag. Minimizing lift-off mass is achieved by balancing optimized staging and an optimized path-to-orbit. This model allows designers to quickly find optimized solutions and to see the effects of design choices.

  12. Identification of the monitoring point density needed to reliably estimate contaminant mass fluxes

    NASA Astrophysics Data System (ADS)

    Liedl, R.; Liu, S.; Fraser, M.; Barker, J.

    2005-12-01

    Plume monitoring frequently relies on the evaluation of point-scale measurements of concentration at observation wells which are located at control planes or `fences' perpendicular to groundwater flow. Depth-specific concentration values are used to estimate the total mass flux of individual contaminants through the fence. Results of this approach, which is based on spatial interpolation, obviously depend on the density of the measurement points. Our contribution relates the accurracy of mass flux estimation to the point density and, in particular, allows to identify a minimum point density needed to achieve a specified accurracy. In order to establish this relationship, concentration data from fences installed in the coal tar creosote plume at the Borden site are used. These fences are characterized by a rather high density of about 7 points/m2 and it is reasonable to assume that the true mass flux is obtained with this point density. This mass flux is then compared with results for less dense grids down to about 0.1points/m2. Mass flux estimates obtained for this range of point densities are analyzed by the moving window method in order to reduce purely random fluctuations. For each position of the moving window the mass flux is estimated and the coefficient of variation (CV) is calculated to quantify variablity of the results. Thus, the CV provides a relative measure of accurracy in the estimated fluxes. By applying this approach to the Borden naphthalene plume at different times, it is found that the point density changes from sufficient to insufficient due to the temporally decreasing mass flux. By comparing the results of naphthalene and phenol at the same fence and at the same time, we can see that the same grid density might be sufficient for one compound but not for another. If a rather strict CV criterion of 5% is used, a grid of 7 points/m2 is shown to allow for reliable estimates of the true mass fluxes only in the beginning of plume development when

  13. Center of mass estimation in closed vortices - A verification in principle and practice

    NASA Technical Reports Server (NTRS)

    Hooker, S. B.; Olson, D. B.

    1984-01-01

    The problem of tracking closed mesoscale vortices using center of mass estimation techniques is studied. Three estimators are evaluated using data from a warm core Gulf Stream ring. The comparisons show that a method based on the intersection of perpendicular bisectors and one using a least-squares fit of a conic section perform comparably. The perpendicular bisector algorithm is used in conjunction with a Gaussian ring model and a star-shaped survey pattern to produce an expected error curve as a function of vortex translation, survey speed and vortex size. For typical ring parameters, center estimation is usually possible to within + or - 5 km. The feasibility of using differing data sets to construct a history of ring motion based on a coordinate system moving with the ring is also investigated. In this way, the validity of using satellite-derived data and drifter trajectories to estimate the center of mass of a mesoscale feature is assessed. The results of the analysis demonstrate that the location of the deeper structure of the ring and the surface expression are sufficiently well correlated to permit dynamically relevant calculations based on surface measurements. It is shown that satellite-derived data can be used to approximate the center of mass trajectory to within the error in the individual center estimates for the period analyzed. The Lagrangian-drifter-derived centers are offset from the center of mass trajectory in a manner consistent with kinematic arguments.

  14. Global estimates of submarine groundwater discharge using numerical modeling and geomatics

    NASA Astrophysics Data System (ADS)

    Luijendijk, E.; Gleeson, T.; Ferguson, G. A.

    2011-12-01

    Submarine groundwater discharge (SGD), the flow of fresh or saline groundwater to an ocean, may be a significant contributor to the water and chemical budgets of the world oceans. SGD consists of fresh, terrestrial groundwater driven by hydraulic gradients, the focus of this research, and re-circulated seawater driven by tidal pumping, wave set-up, convection and hydraulic gradients. We couple density-dependent analytical and numerical simulations of generic models of coastal topography and geology with geomatic data bases to resolve the rate and driving mechanisms of terrestrially-derived submarine groundwater discharge globally. Two analytical models lead to linear relationships between SGD and the key predictive parameters: hydraulic gradients, hydraulic conductivities, aquifer thickness and recharge. Average global geomatic parameters suggest global SGD ranges from 0.01% to 0.2% of global river run off which much lower than most previous estimates of global SGD. Quantifying submarine groundwater discharge is critical because SGD is a poorly constrained flux that can significantly contribute to eutrophication or water quality decline in coastal areas.

  15. Mass discharge estimation from contaminated sites: Multi-model solutions for assessment of conceptual uncertainty

    NASA Astrophysics Data System (ADS)

    Thomsen, N. I.; Troldborg, M.; McKnight, U. S.; Binning, P. J.; Bjerg, P. L.

    2012-04-01

    Mass discharge estimates are increasingly being used in the management of contaminated sites. Such estimates have proven useful for supporting decisions related to the prioritization of contaminated sites in a groundwater catchment. Potential management options can be categorised as follows: (1) leave as is, (2) clean up, or (3) further investigation needed. However, mass discharge estimates are often very uncertain, which may hamper the management decisions. If option 1 is incorrectly chosen soil and water quality will decrease, threatening or destroying drinking water resources. The risk of choosing option 2 is to spend money on remediating a site that does not pose a problem. Choosing option 3 will often be safest, but may not be the optimal economic solution. Quantification of the uncertainty in mass discharge estimates can therefore greatly improve the foundation for selecting the appropriate management option. The uncertainty of mass discharge estimates depends greatly on the extent of the site characterization. A good approach for uncertainty estimation will be flexible with respect to the investigation level, and account for both parameter and conceptual model uncertainty. We propose a method for quantifying the uncertainty of dynamic mass discharge estimates from contaminant point sources on the local scale. The method considers both parameter and conceptual uncertainty through a multi-model approach. The multi-model approach evaluates multiple conceptual models for the same site. The different conceptual models consider different source characterizations and hydrogeological descriptions. The idea is to include a set of essentially different conceptual models where each model is believed to be realistic representation of the given site, based on the current level of information. Parameter uncertainty is quantified using Monte Carlo simulations. For each conceptual model we calculate a transient mass discharge estimate with uncertainty bounds resulting from

  16. An Integrated Risk Function for Estimating the Global Burden of Disease Attributable to Ambient Fine Particulate Matter Exposure

    PubMed Central

    Pope, C. Arden; Ezzati, Majid; Olives, Casey; Lim, Stephen S.; Mehta, Sumi; Shin, Hwashin H.; Singh, Gitanjali; Hubbell, Bryan; Brauer, Michael; Anderson, H. Ross; Smith, Kirk R.; Balmes, John R.; Bruce, Nigel G.; Kan, Haidong; Laden, Francine; Prüss-Ustün, Annette; Turner, Michelle C.; Gapstur, Susan M.; Diver, W. Ryan; Cohen, Aaron

    2014-01-01

    Background: Estimating the burden of disease attributable to long-term exposure to fine particulate matter (PM2.5) in ambient air requires knowledge of both the shape and magnitude of the relative risk (RR) function. However, adequate direct evidence to identify the shape of the mortality RR functions at the high ambient concentrations observed in many places in the world is lacking. Objective: We developed RR functions over the entire global exposure range for causes of mortality in adults: ischemic heart disease (IHD), cerebrovascular disease (stroke), chronic obstructive pulmonary disease (COPD), and lung cancer (LC). We also developed RR functions for the incidence of acute lower respiratory infection (ALRI) that can be used to estimate mortality and lost-years of healthy life in children < 5 years of age. Methods: We fit an integrated exposure–response (IER) model by integrating available RR information from studies of ambient air pollution (AAP), second hand tobacco smoke, household solid cooking fuel, and active smoking (AS). AS exposures were converted to estimated annual PM2.5 exposure equivalents using inhaled doses of particle mass. We derived population attributable fractions (PAFs) for every country based on estimated worldwide ambient PM2.5 concentrations. Results: The IER model was a superior predictor of RR compared with seven other forms previously used in burden assessments. The percent PAF attributable to AAP exposure varied among countries from 2 to 41 for IHD, 1 to 43 for stroke, < 1 to 21 for COPD, < 1 to 25 for LC, and < 1 to 38 for ALRI. Conclusions: We developed a fine particulate mass–based RR model that covered the global range of exposure by integrating RR information from different combustion types that generate emissions of particulate matter. The model can be updated as new RR information becomes available. Citation: Burnett RT, Pope CA III, Ezzati M, Olives C, Lim SS, Mehta S, Shin HH, Singh G, Hubbell B, Brauer M, Anderson HR

  17. DARK MATTER MASS FRACTION IN LENS GALAXIES: NEW ESTIMATES FROM MICROLENSING

    SciTech Connect

    Jiménez-Vicente, J.; Mediavilla, E.; Muñoz, J. A.

    2015-02-01

    We present a joint estimate of the stellar/dark matter mass fraction in lens galaxies and the average size of the accretion disk of lensed quasars based on microlensing measurements of 27 quasar image pairs seen through 19 lens galaxies. The Bayesian estimate for the fraction of the surface mass density in the form of stars is α = 0.21 ± 0.14 near the Einstein radius of the lenses (∼1-2 effective radii). The estimate for the average accretion disk size is R{sub 1/2}=7.9{sub −2.6}{sup +3.8}√(M/0.3 M{sub ⊙}) light days. The fraction of mass in stars at these radii is significantly larger than previous estimates from microlensing studies assuming quasars were point-like. The corresponding local dark matter fraction of 79% is in good agreement with other estimates based on strong lensing or kinematics. The size of the accretion disk inferred in the present study is slightly larger than previous estimates.

  18. Global nitrogen cycle: pre-Anthropocene mass and isotope fluxes and effects of human perturbations

    NASA Astrophysics Data System (ADS)

    Joo, Y.; Li, D. D.; Lerman, A.; Mackenzie, F. T.

    2012-12-01

    The size of the largest nitrogen reservoir -- the Earth atmosphere -- and its long residence time of approximately 17 million years suggest that the global N cycle was likely to be balanced at geological time scales. After the industrial revolution, human activities, such as mining, fossil fuel burning, land use change, and artificial fertilization, have resulted in perturbations and numerous flux changes of the N cycle. The effects of human activities on the mass and isotopic composition of the N reservoirs can be predicted using a detailed N cycle model with estimated additions. For the pre-Anthropocene period, a balanced steady-state N cycle model was constructed based on the Redfield ratios and an extensive literature review. The model includes 14 N reservoirs in the domains of the atmosphere, land, and ocean. The biotic reservoirs on land and in the ocean (land plants and marine biota) interact with atmospheric N2 and dissolved inorganic N (DIN) in ocean and soil waters. DIN further interacts with dissolved organic N (DON), particulate organic matter (POM), and ocean sediments. Atmosphere supplies N to land and ocean domains mainly by N fixation, deposition, and dissolution, and these fluxes are balanced by denitrification and volatilization back to atmosphere. Riverine transport of dissolved and particulate N connects land and ocean domains. Once the cycle is mass-balanced, the isotopic composition of reservoir and the size of fractionation accompanying microbial transformations and transfers of N species between the reservoirs were estimated by numerical iteration of the flux equations based on the reported δ15N values and fractionation factors. The calculated fractionation factors tend to be smaller in magnitude than the experimentally measured ones in natural systems, which can be interpreted as an indication of N-limited conditions prevailing in pre-Anthropocene world: a smaller isotope fractionation can be interpreted as an indication of nitrogen

  19. A global thermospheric model based on mass spectrometer and incoherent scatter data MSIS. II - Composition

    NASA Technical Reports Server (NTRS)

    Hedin, A. E.; Reber, C. A.; Newton, G. P.; Spencer, N. W.; Brinton, H. C.; Mayr, H. G.; Potter, W. E.

    1977-01-01

    Measurements of O, He, and Ar from neutral gas mass spectrometers on four satellites (Ogo 6, San Marco 3, Aeros A, and AEC-C) and inferred oxygen and hydrogen densities from an ion mass spectrometer on AE-C have been combined with a neutral temperature and nitrogen density model to produce a global model of thermospheric composition in terms of inferred variations at 120 km. The data set covers the time period from mid-1969 to mid-1975. The MSIS (mass spectrometer and incoherent scatter data) model is compared with the Ogo 6 model (Hedin et al., 1974). Ar variations at 120 km tend to be in phase with temperature variations and inverse to the He, O, and H variations.

  20. The nonlinear equation of state of sea water and the global water mass distribution

    NASA Astrophysics Data System (ADS)

    Nycander, Jonas; Hieronymus, Magnus; Roquet, Fabien

    2015-09-01

    The role of nonlinearities of the equation of state (EOS) of seawater for the distribution of water masses in the global ocean is examined through simulations with an ocean general circulation model with various manipulated versions of the EOS. A simulation with a strongly simplified EOS, which contains only two nonlinear terms, still produces a realistic water mass distribution, demonstrating that these two nonlinearities are indeed the essential ones. Further simulations show that each of these two nonlinear terms affects a specific aspect of the water mass distribution: the cabbeling term is crucial for the formation of Antarctic Intermediate Water and the thermobaric term for the layering of North Atlantic Deep Water and Antarctic Bottom Water.

  1. Measuring the Mass of a Galaxy: An evaluation of the performance of Bayesian mass estimates using statistical simulation

    NASA Astrophysics Data System (ADS)

    Eadie, Gwendolyn Marie

    This research uses a Bayesian approach to study the biases that may occur when kinematic data is used to estimate the mass of a galaxy. Data is simulated from the Hernquist (1990) distribution functions (DFs) for velocity dispersions of the isotropic, constant anisotropic, and anisotropic Osipkov (1979) and Merritt (1985) type, and then analysed using the isotropic Hernquist model. Biases are explored when i) the model and data come from the same DF, ii) the model and data come from the same DF but tangential velocities are unknown, iii) the model and data come from different DFs, and iv) the model and data come from different DFs and the tangential velocities are unknown. Mock observations are also created from the Gauthier (2006) simulations and analysed with the isotropic Hernquist model. No bias was found in situation (i), a slight positive bias was found in (ii), a negative bias was found in (iii), and a large positive bias was found in (iv). The mass estimate of the Gauthier system when tangential velocities were unknown was nearly correct, but the mass profile was not described well by the isotropic Hernquist model. When the Gauthier data was analysed with the tangential velocities, the mass of the system was overestimated. The code created for the research runs three parallel Markov Chains for each data set, uses the Gelman-Rubin statistic to assess convergence, and combines the converged chains into a single sample of the posterior distribution for each data set. The code also includes two ways to deal with nuisance parameters. One is to marginalize over the nuisance parameter at every step in the chain, and the other is to sample the nuisance parameters using a hybrid-Gibbs sampler. When tangential velocities, v(t), are unobserved in the analyses above, they are sampled as nuisance parameters in the Markov Chain. The v(t) estimates from the Markov chains did a poor job of estimating the true tangential velocities. However, the posterior samples of v

  2. A Temperature-Based Model for Estimating Monthly Average Daily Global Solar Radiation in China

    PubMed Central

    Li, Huashan; Cao, Fei; Wang, Xianlong; Ma, Weibin

    2014-01-01

    Since air temperature records are readily available around the world, the models based on air temperature for estimating solar radiation have been widely accepted. In this paper, a new model based on Hargreaves and Samani (HS) method for estimating monthly average daily global solar radiation is proposed. With statistical error tests, the performance of the new model is validated by comparing with the HS model and its two modifications (Samani model and Chen model) against the measured data at 65 meteorological stations in China. Results show that the new model is more accurate and robust than the HS, Samani, and Chen models in all climatic regions, especially in the humid regions. Hence, the new model can be recommended for estimating solar radiation in areas where only air temperature data are available in China. PMID:24605046

  3. Graptolite community responses to global climate change and the Late Ordovician mass extinction

    NASA Astrophysics Data System (ADS)

    Sheets, H. David; Mitchell, Charles E.; Melchin, Michael J.; Loxton, Jason; Štorch, Petr; Carlucci, Kristi L.; Hawkins, Andrew D.

    2016-07-01

    Mass extinctions disrupt ecological communities. Although climate changes produce stress in ecological communities, few paleobiological studies have systematically addressed the impact of global climate changes on the fine details of community structure with a view to understanding how changes in community structure presage, or even cause, biodiversity decline during mass extinctions. Based on a novel Bayesian approach to biotope assessment, we present a study of changes in species abundance distribution patterns of macroplanktonic graptolite faunas (˜447–444 Ma) leading into the Late Ordovician mass extinction. Communities at two contrasting sites exhibit significant decreases in complexity and evenness as a consequence of the preferential decline in abundance of dysaerobic zone specialist species. The observed changes in community complexity and evenness commenced well before the dramatic population depletions that mark the tipping point of the extinction event. Initially, community changes tracked changes in the oceanic water masses, but these relations broke down during the onset of mass extinction. Environmental isotope and biomarker data suggest that sea surface temperature and nutrient cycling in the paleotropical oceans changed sharply during the latest Katian time, with consequent changes in the extent of the oxygen minimum zone and phytoplankton community composition. Although many impacted species persisted in ephemeral populations, increased extinction risk selectively depleted the diversity of paleotropical graptolite species during the latest Katian and early Hirnantian. The effects of long-term climate change on habitats can thus degrade populations in ways that cascade through communities, with effects that culminate in mass extinction.

  4. Graptolite community responses to global climate change and the Late Ordovician mass extinction.

    PubMed

    Sheets, H David; Mitchell, Charles E; Melchin, Michael J; Loxton, Jason; Štorch, Petr; Carlucci, Kristi L; Hawkins, Andrew D

    2016-07-26

    Mass extinctions disrupt ecological communities. Although climate changes produce stress in ecological communities, few paleobiological studies have systematically addressed the impact of global climate changes on the fine details of community structure with a view to understanding how changes in community structure presage, or even cause, biodiversity decline during mass extinctions. Based on a novel Bayesian approach to biotope assessment, we present a study of changes in species abundance distribution patterns of macroplanktonic graptolite faunas (∼447-444 Ma) leading into the Late Ordovician mass extinction. Communities at two contrasting sites exhibit significant decreases in complexity and evenness as a consequence of the preferential decline in abundance of dysaerobic zone specialist species. The observed changes in community complexity and evenness commenced well before the dramatic population depletions that mark the tipping point of the extinction event. Initially, community changes tracked changes in the oceanic water masses, but these relations broke down during the onset of mass extinction. Environmental isotope and biomarker data suggest that sea surface temperature and nutrient cycling in the paleotropical oceans changed sharply during the latest Katian time, with consequent changes in the extent of the oxygen minimum zone and phytoplankton community composition. Although many impacted species persisted in ephemeral populations, increased extinction risk selectively depleted the diversity of paleotropical graptolite species during the latest Katian and early Hirnantian. The effects of long-term climate change on habitats can thus degrade populations in ways that cascade through communities, with effects that culminate in mass extinction. PMID:27432981

  5. World Health Organization Global Estimates and Regional Comparisons of the Burden of Foodborne Disease in 2010

    PubMed Central

    Havelaar, Arie H.; Kirk, Martyn D.; Torgerson, Paul R.; Gibb, Herman J.; Hald, Tine; Lake, Robin J.; Praet, Nicolas; Bellinger, David C.; de Silva, Nilanthi R.; Gargouri, Neyla; Speybroeck, Niko; Cawthorne, Amy; Mathers, Colin; Stein, Claudia; Angulo, Frederick J.; Devleesschauwer, Brecht

    2015-01-01

    Illness and death from diseases caused by contaminated food are a constant threat to public health and a significant impediment to socio-economic development worldwide. To measure the global and regional burden of foodborne disease (FBD), the World Health Organization (WHO) established the Foodborne Disease Burden Epidemiology Reference Group (FERG), which here reports their first estimates of the incidence, mortality, and disease burden due to 31 foodborne hazards. We find that the global burden of FBD is comparable to those of the major infectious diseases, HIV/AIDS, malaria and tuberculosis. The most frequent causes of foodborne illness were diarrheal disease agents, particularly norovirus and Campylobacter spp. Diarrheal disease agents, especially non-typhoidal Salmonella enterica, were also responsible for the majority of deaths due to FBD. Other major causes of FBD deaths were Salmonella Typhi, Taenia solium and hepatitis A virus. The global burden of FBD caused by the 31 hazards in 2010 was 33 million Disability Adjusted Life Years (DALYs); children under five years old bore 40% of this burden. The 14 subregions, defined on the basis of child and adult mortality, had considerably different burdens of FBD, with the greatest falling on the subregions in Africa, followed by the subregions in South-East Asia and the Eastern Mediterranean D subregion. Some hazards, such as non-typhoidal S. enterica, were important causes of FBD in all regions of the world, whereas others, such as certain parasitic helminths, were highly localised. Thus, the burden of FBD is borne particularly by children under five years old–although they represent only 9% of the global population–and people living in low-income regions of the world. These estimates are conservative, i.e., underestimates rather than overestimates; further studies are needed to address the data gaps and limitations of the study. Nevertheless, all stakeholders can contribute to improvements in food safety

  6. World Health Organization Global Estimates and Regional Comparisons of the Burden of Foodborne Disease in 2010.

    PubMed

    Havelaar, Arie H; Kirk, Martyn D; Torgerson, Paul R; Gibb, Herman J; Hald, Tine; Lake, Robin J; Praet, Nicolas; Bellinger, David C; de Silva, Nilanthi R; Gargouri, Neyla; Speybroeck, Niko; Cawthorne, Amy; Mathers, Colin; Stein, Claudia; Angulo, Frederick J; Devleesschauwer, Brecht

    2015-12-01

    Illness and death from diseases caused by contaminated food are a constant threat to public health and a significant impediment to socio-economic development worldwide. To measure the global and regional burden of foodborne disease (FBD), the World Health Organization (WHO) established the Foodborne Disease Burden Epidemiology Reference Group (FERG), which here reports their first estimates of the incidence, mortality, and disease burden due to 31 foodborne hazards. We find that the global burden of FBD is comparable to those of the major infectious diseases, HIV/AIDS, malaria and tuberculosis. The most frequent causes of foodborne illness were diarrheal disease agents, particularly norovirus and Campylobacter spp. Diarrheal disease agents, especially non-typhoidal Salmonella enterica, were also responsible for the majority of deaths due to FBD. Other major causes of FBD deaths were Salmonella Typhi, Taenia solium and hepatitis A virus. The global burden of FBD caused by the 31 hazards in 2010 was 33 million Disability Adjusted Life Years (DALYs); children under five years old bore 40% of this burden. The 14 subregions, defined on the basis of child and adult mortality, had considerably different burdens of FBD, with the greatest falling on the subregions in Africa, followed by the subregions in South-East Asia and the Eastern Mediterranean D subregion. Some hazards, such as non-typhoidal S. enterica, were important causes of FBD in all regions of the world, whereas others, such as certain parasitic helminths, were highly localised. Thus, the burden of FBD is borne particularly by children under five years old-although they represent only 9% of the global population-and people living in low-income regions of the world. These estimates are conservative, i.e., underestimates rather than overestimates; further studies are needed to address the data gaps and limitations of the study. Nevertheless, all stakeholders can contribute to improvements in food safety

  7. Estimation of global river transport of sediments and associated particulate C, N, and P

    NASA Astrophysics Data System (ADS)

    Beusen, A. H. W.; Dekkers, A. L. M.; Bouwman, A. F.; Ludwig, W.; Harrison, J.

    2005-12-01

    This paper presents a multiple linear regression model developed for describing global river export of sediments (suspended solids, TSS) to coastal seas, and approaches for estimating organic carbon, nitrogen, and phosphorous transported as particulate matter (POC, PN, and PP) associated with sediments. The model, with river-basin spatial scale and a 1-year temporal scale, is based on five factors with a significant influence on TSS yields (the extent of marginal grassland and wetland rice, Fournier precipitation, Fournier slope, and lithology), and accounts for sediment trapping in reservoirs. The model generates predictions within a factor of 4 for 80% of the 124 rivers in the data set. It is a robust model which was cross-validated by using training and validation sets of data, and validated against independent data. In addition, Monte Carlo simulations were used to deal with uncertainties in the model coefficients for the five model factors. The global river export of TSS calculated thus is 19 Pg yr-1 with a 95% confidence interval of 11-27 Pg yr-1 when accounting for sediment trapping in regulated rivers. Associated POC, PN, and PP export is 197 Tg yr-1 (as C), 30 Tg yr-1 (N), and 9 Tg yr-1 (P), respectively. The global sediment trapping included in these estimates is 13%. Most particulate nutrients are transported by rivers to the Pacific (˜37% of global particulate nutrient export), Atlantic (28-29%), and Indian (˜20%) oceans, and the major source regions are Asia (˜50% of global particulate nutrient export), South America (˜20%), and Africa (12%).

  8. Spurious barometric pressure acceleration in Antarctica and propagation into GRACE Antarctic mass change estimates

    NASA Astrophysics Data System (ADS)

    Kim, Byeong-Hoon; Eom, Jooyoung; Seo, Ki-Weon; Wilson, Clark R.

    2016-08-01

    Apparent acceleration in Gravity Recovery and Climate Experiment (GRACE) Antarctic ice mass time-series may reflect both ice discharge and surface mass balance contributions. However, a recent study suggests there is also contamination from errors in atmospheric pressure de-aliasing fields [European Center for Medium-Range Weather Forecast (ECMWF) operational products] used during GRACE data processing. To further examine this question, we compare GRACE atmospheric pressure de-aliasing (GAA) fields with in situ surface pressure data from coastal and inland stations. Differences between the two are likely due to GAA errors, and provide a measure of error in GRACE solutions. Time-series of differences at individual weather stations are fit to four presumed error components: annual sinusoids, a linear trend, an acceleration term and jumps at times of known ECMWF model changes. Using data from inland stations, we estimate that atmospheric pressure error causes an acceleration error of about +7.0 Gt yr-2, which is large relative to prior GRACE estimates of Antarctic ice mass acceleration in the range of -12 to -14 Gt yr-2. We also estimate apparent acceleration rates from other barometric pressure (reanalysis) fields, including ERA-Interim, MERRA and NCEP/DOE. When integrated over East Antarctica, the four mass acceleration estimates (from GAA and the three reanalysis fields) vary considerably (by ˜2-16 Gt yr-2). This shows the need for further effort to improve atmospheric mass estimates in this region of sparse in situ observations, in order to use GRACE observations to measure ice mass acceleration and related sea level change.

  9. The Fire INventory from NCAR (FINN) - a high resolution global model to estimate the emissions from open burning

    NASA Astrophysics Data System (ADS)

    Wiedinmyer, C.; Akagi, S. K.; Yokelson, R. J.; Emmons, L. K.; Al-Saadi, J. A.; Orlando, J. J.; Soja, A. J.

    2010-12-01

    The Fire INventory from NCAR version 1.0 (FINNv1) provides daily, 1 km resolution, global estimates of the trace gas and particle emissions from open burning of biomass, which includes wildfire, agricultural fires, and prescribed burning and does not include biofuel use and trash burning. Emission factors used in the calculations have been updated with recent data, particularly for the non-methane organic compounds (NMOC). The resulting global annual NMOC emission estimates are as much as a factor of 5 greater than some prior estimates. Chemical speciation profiles, necessary to allocate the total NMOC emission estimates to lumped species for use by chemical transport models, are provided for three widely used chemical mechanisms: SAPRC99, GEOS-CHEM, and MOZART-4. Using these profiles, FINNv1 also provides global estimates of key organic compounds, including formaldehyde and methanol. The uncertainty in the FINNv1 emission estimates are about a factor of two; but, the estimates agree closely with other global inventories of biomass burning emissions for CO, CO2, and other species with less variable emission factors. FINNv1 emission estimates have been developed specifically for modeling atmospheric chemistry and air quality in a consistent framework at scales from local to global. The product is unique because of the high temporal and spatial resolution, global coverage, and the number of species estimated. FINNv1 can be used for both hindcast and forecast or near-real time model applications and the results are being critically evaluated with models and observations whenever possible.

  10. Global Trends and Variability In the Mass Balance of Mountain and Valley Glaciers

    NASA Astrophysics Data System (ADS)

    Medwedeff, W. G.; Roe, G.

    2015-12-01

    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, with a particular interest given to mountain and valley glaciers. 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.

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

    NASA Astrophysics Data System (ADS)

    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. Spatial Estimation of Sub-Hour Global Horizontal Irradiance Based on Official Observations and Remote Sensors

    PubMed Central

    Gutierrez-Corea, Federico-Vladimir; Manso-Callejo, Miguel-Angel; Moreno-Regidor, María-Pilar; Velasco-Gómez, Jesús

    2014-01-01

    This study was motivated by the need to improve densification of Global Horizontal Irradiance (GHI) observations, increasing the number of surface weather stations that observe it, using sensors with a sub-hour periodicity and examining the methods of spatial GHI estimation (by interpolation) with that periodicity in other locations. The aim of the present research project is to analyze the goodness of 15-minute GHI spatial estimations for five methods in the territory of Spain (three geo-statistical interpolation methods, one deterministic method and the HelioSat2 method, which is based on satellite images). The research concludes that, when the work area has adequate station density, the best method for estimating GHI every 15 min is Regression Kriging interpolation using GHI estimated from satellite images as one of the input variables. On the contrary, when station density is low, the best method is estimating GHI directly from satellite images. A comparison between the GHI observed by volunteer stations and the estimation model applied concludes that 67% of the volunteer stations analyzed present values within the margin of error (average of ±2 standard deviations). PMID:24732102

  13. Estimating the Capacity of Gross Primary Production from Global Observation Satellite

    NASA Astrophysics Data System (ADS)

    Muramatsu, Kanako; Soyama, Noriko; Thanyaparaneedkul, Juthasinee; Furumi, Shinobu; Daigo, Motomasa

    2012-07-01

    Estimation of Gross Primary Production with high accuracy is important for understanding the carbon cycle. For estimating gross primary production, photosynthesis process was considers into two parts. One is the capacity and another is the reduction which is influenced by environmental conditions such as weather conditions of vapor pressure difference and soil moisture. The capacity estimation part is reported in this conference. For a leaf, it is well known photosynthesis capacity is mainly depend on amount of chlorophyll and enzyme. Chlorophyll contents reflect the color of a leaf. Since we focus on the chlorophyll contents for estimating the capacity of the gross primary production. It was reported by J. Thanyapraneedkul (2012) that vegetation index of the ratio of green band and near infrared was linear relationship with chlorophyll contents of a leaf, and was a linear relationship with the maximum photosynthesis at light saturation of light response curve with less stress conditions using flux data. The index is suitable for global observing satellite, because the spectral bands are available. Using the index and empirical relationship developed by J. Thanyapraneedkul, the light response curve with less stress can be estimated from the vegetation index. In this study, firstly, the global distribution of the index was studied. The regions of high index value in winter time were correspond to tropical rainforest. Next, the capacity of gross primary production was estimated using the light response curve using the index. The GPP capacity of the almost all regions was higher than MODIS GPP. For the tropical rain forest regions, the GPP capacity value was similar with MODIS GPP product.

  14. A New Estimate for Global Hydrothermal Exchange Between the Oceans and Lithosphere

    NASA Astrophysics Data System (ADS)

    Hasterok, D. P.

    2013-12-01

    We revise the estimated global power deficit due to ventilated hydrothermal circulation (8.0 TW) using an updated global heat flow dataset with >14000 oceanic measurements and a new conductive cooling model of the oceanic lithosphere. This study differs from previous estimates by taking into account (1) non-Gaussian statistics, (2) an improved seafloor age model, (3) a new plate cooling model calibrated directly to heat flow, and (4) the effect of sediment cover on the heat flow deficit and ventilated cutoff age. We obtain the maximum heat flow deficit (difference between predicted and observed) when the data are separated by seafloor areas with <400 m and 400 m of sediment cover. The estimated power deficit (integrated heat flow deficit with respect to area) for areas of thin (<400 m) sediment cover is 7.8 TW and for areas of thick (400 m) is 0.2 TW. The total power deficit, 8.0 TW with 50% of estimates falling between 5.0 and 10.0 TW, represents a 30% reduction in magnitude compared with previous heat flow and fluid flow based estimates. Regions with thick, 400 m, sediment cover experience half the heat flow deficit for one-third of the duration (25 Ma) of regions with thin sediment cover (75 Ma). Based on this study, vigorous fluid exchange between the oceans and seafloor redistributes 30% of heat lost through young oceanic crust. Spatial variation in heat flow deficit relative to estimated conductive heat loss. Variations are calibrated to observed heat flow and constrained by sediment thickness variations.

  15. Cluster Structure in Cosmological Simulations. I. Correlation to Observables, Mass Estimates, and Evolution

    NASA Astrophysics Data System (ADS)

    Jeltema, Tesla E.; Hallman, Eric J.; Burns, Jack O.; Motl, Patrick M.

    2008-07-01

    We use Enzo, a hybrid Eulerian adaptive mesh refinement/N-body code including nongravitational heating and cooling, to explore the morphology of the X-ray gas in clusters of galaxies and its evolution in current-generation cosmological simulations. We employ and compare two observationally motivated structure measures: power ratios and centroid shift. Overall, the structure of our simulated clusters compares remarkably well to low-redshift observations, although some differences remain that may point to incomplete gas physics. We find no dependence on cluster structure in the mass-observable scaling relations, TX-M and YX-M, when using the true cluster masses. However, estimates of the total mass based on the assumption of hydrostatic equilibrium, as assumed in observational studies, are systematically low. We show that the hydrostatic mass bias strongly correlates with cluster structure and, more weakly, with cluster mass. When the hydrostatic masses are used, the mass-observable scaling relations and gas mass fractions depend significantly on cluster morphology, and the true relations are not recovered even if the most relaxed clusters are used. We show that cluster structure, via the power ratios, can be used to effectively correct the hydrostatic mass estimates and mass scaling relations, suggesting that we can calibrate for this systematic effect in cosmological studies. Similar to observational studies, we find that cluster structure, particularly centroid shift, evolves with redshift. This evolution is mild but will lead to additional errors at high redshift. Projection along the line of sight leads to significant uncertainty in the structure of individual clusters: less than 50% of clusters which appear relaxed in projection based on our structure measures are truly relaxed.

  16. Impact of climatic noise on global estimates of terrestrial water balance components

    NASA Astrophysics Data System (ADS)

    Nasonova, Olga; Gusev, Yeugeniy; Semenov, Vladimir; Kovalev, Evgeny

    2016-04-01

    Estimates of water balance components performed by different authors in climate impact studies are characterized by a large scatter or uncertainty associated, in particular, with application of different meteorological forcing data (simulated by climate models), different estimates of model parameters, and different hydrological models. In the present work, the objective uncertainty, which cannot be reduced by means of better physical description of the processes under study or by means of improvement of the quality of input data for model simulations, and which is an internal feature of the atmosphere - hydrosphere - land surface system, is considered. This uncertainty is caused by a chaotic character of atmospheric processes (i.e. by so-called climatic noise), their instability with respect to small errors in determination of initial conditions for modeling the evolution of meteorological variables. Our study is devoted to investigating the impact of climatic noise on the estimates of terrestrial water balance components (precipitation, runoff and evapotranspiration) on a global scale. To achieve the effect of climatic noise 45 simulations were performed by the atmospheric general circulation model ECHAM5 under identical lower boundary conditions (including sea surface temperatures and sea ice concentrations) and constant external forcing parameters. The only differences between the simulations were initial conditions of the atmosphere. Meteorological fields simulated by ECHAM5 for the period of 1979-2012 were used as forcing data (with 6-hour temporal resolution and one-degree spatial one) by the land surface model Soil Water - Atmosphere - Plants (SWAP) for hydrological simulations on a global scale. As a result, 45-member ensemble of the water balance components for the land surface of the Earth excluding Antarctica was obtained. Analysis of the obtained results allowed us to estimate the lowest level of uncertainty which can be achieved in climate impact

  17. Global Warming Estimation from MSU: Correction for Drift and Calibration Errors

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Microwave Sounding Unit (MSU) radiometer observations in Ch 2 (53.74 GHz), made in the nadir direction from sequential, sun-synchronous, polar-orbiting NOAA morning satellites (NOAA 6, 10 and 12 that have about 7am/7pm orbital geometry) and afternoon satellites (NOAA 7, 9, 11 and 14 that have about 2am/2pm orbital geometry) are analyzed in this study to derive global temperature trend from 1980 to 1998. In order to remove the discontinuities between the data of the successive satellites and to get a continuous time series, first we have used shortest possible time record of each satellite. In this way we get a preliminary estimate of the global temperature trend of 0.21 K/decade. However, this estimate is affected by systematic time-dependent errors. One such error is the instrument calibration error. This error can be inferred whenever there are overlapping measurements made by two satellites over an extended period of time. From the available successive satellite data we have taken the longest possible time record of each satellite to form the time series during the period 1980 to 1998 to this error. We find we can decrease the global temperature trend by about 0.07 K/decade. In addition there are systematic time dependent errors present in the data that are introduced by the drift in the satellite orbital geometry arises from the diurnal cycle in temperature which is the drift related change in the calibration of the MSU. In order to analyze the nature of these drift related errors the multi-satellite Ch 2 data set is partitioned into am and pm subsets to create two independent time series. The error can be assessed in the am and pm data of Ch 2 on land and can be eliminated. Observations made in the MSU Ch 1 (50.3 GHz) support this approach. The error is obvious only in the difference between the pm and am observations of Ch 2 over the ocean. We have followed two different paths to assess the impact of the errors on the global temperature trend. In one path the

  18. Global Warming Estimation from MSU: Correction for Drift and Calibration Errors

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

    2000-01-01

    Microwave Sounding Unit (MSU) radiometer observations in Ch 2 (53.74 GHz), made in the nadir direction from sequential, sun-synchronous, polar-orbiting NOAA morning satellites (NOAA 6, 10 and 12 that have approximately 7am/7pm orbital geometry) and. afternoon satellites (NOAA 7, 9, 11 and 14 that have approximately 2am/2pm orbital geometry) are analyzed in this study to derive global temperature trend from 1980 to 1998. In order to remove the discontinuities between the data of the successive satellites and to get a continuous time series, first we have used shortest possible time record of each satellite. In this way we get a preliminary estimate of the global temperature trend of 0.21 K/decade. However, this estimate is affected by systematic time-dependent errors. One such error is the instrument calibration error eo. This error can be inferred whenever there are overlapping measurements made by two satellites over an extended period of time. From the available successive satellite data we have taken the longest possible time record of each satellite to form the time series during the period 1980 to 1998 to this error eo. We find eo can decrease the global temperature trend by approximately 0.07 K/decade. In addition there are systematic time dependent errors ed and ec present in the data that are introduced by the drift in the satellite orbital geometry. ed arises from the diurnal cycle in temperature and ec is the drift related change in the calibration of the MSU. In order to analyze the nature of these drift related errors the multi-satellite Ch 2 data set is partitioned into am and pm subsets to create two independent time series. The error ed can be assessed in the am and pm data of Ch 2 on land and can be eliminated. Observation made in the MSU Ch 1 (50.3 GHz) support this approach. The error ec is obvious only in the difference between the pm and am observations of Ch 2 over the ocean. We have followed two different paths to assess the impact of the

  19. Investigation of Aerosol Surface Area Estimation from Number and Mass Concentration Measurements: Particle Density Effect

    PubMed Central

    Ku, Bon Ki; Evans, Douglas E.

    2015-01-01

    For nanoparticles with nonspherical morphologies, e.g., open agglomerates or fibrous particles, it is expected that the actual density of agglomerates may be significantly different from the bulk material density. It is further expected that using the material density may upset the relationship between surface area and mass when a method for estimating aerosol surface area from number and mass concentrations (referred to as “Maynard’s estimation method”) is used. Therefore, it is necessary to quantitatively investigate how much the Maynard’s estimation method depends on particle morphology and density. In this study, aerosol surface area estimated from number and mass concentration measurements was evaluated and compared with values from two reference methods: a method proposed by Lall and Friedlander for agglomerates and a mobility based method for compact nonspherical particles using well-defined polydisperse aerosols with known particle densities. Polydisperse silver aerosol particles were generated by an aerosol generation facility. Generated aerosols had a range of morphologies, count median diameters (CMD) between 25 and 50 nm, and geometric standard deviations (GSD) between 1.5 and 1.8. The surface area estimates from number and mass concentration measurements correlated well with the two reference values when gravimetric mass was used. The aerosol surface area estimates from the Maynard’s estimation method were comparable to the reference method for all particle morphologies within the surface area ratios of 3.31 and 0.19 for assumed GSDs 1.5 and 1.8, respectively, when the bulk material density of silver was used. The difference between the Maynard’s estimation method and surface area measured by the reference method for fractal-like agglomerates decreased from 79% to 23% when the measured effective particle density was used, while the difference for nearly spherical particles decreased from 30% to 24%. The results indicate that the use of

  20. Does Ocean Color Data Assimilation Improve Estimates of Global Ocean Inorganic Carbon?

    NASA Technical Reports Server (NTRS)

    Gregg, Watson

    2012-01-01

    Ocean color data assimilation has been shown to dramatically improve chlorophyll abundances and distributions globally and regionally in the oceans. Chlorophyll is a proxy for phytoplankton biomass (which is explicitly defined in a model), and is related to the inorganic carbon cycle through the interactions of the organic carbon (particulate and dissolved) and through primary production where inorganic carbon is directly taken out of the system. Does ocean color data assimilation, whose effects on estimates of chlorophyll are demonstrable, trickle through the simulated ocean carbon system to produce improved estimates of inorganic carbon? Our emphasis here is dissolved inorganic carbon, pC02, and the air-sea flux. We use a sequential data assimilation method that assimilates chlorophyll directly and indirectly changes nutrient concentrations in a multi-variate approach. The results are decidedly mixed. Dissolved organic carbon estimates from the assimilation model are not meaningfully different from free-run, or unassimilated results, and comparisons with in situ data are similar. pC02 estimates are generally worse after data assimilation, with global estimates diverging 6.4% from in situ data, while free-run estimates are only 4.7% higher. Basin correlations are, however, slightly improved: r increase from 0.78 to 0.79, and slope closer to unity at 0.94 compared to 0.86. In contrast, air-sea flux of C02 is noticeably improved after data assimilation. Global differences decline from -0.635 mol/m2/y (stronger model sink from the atmosphere) to -0.202 mol/m2/y. Basin correlations are slightly improved from r=O.77 to r=0.78, with slope closer to unity (from 0.93 to 0.99). The Equatorial Atlantic appears as a slight sink in the free-run, but is correctly represented as a moderate source in the assimilation model. However, the assimilation model shows the Antarctic to be a source, rather than a modest sink and the North Indian basin is represented incorrectly as a sink

  1. A Comparison of Satellite-Based Radar and Passive Microwave Estimates of Global Wilson Current Source

    NASA Astrophysics Data System (ADS)

    Peterson, M. J.; Deierling, W.; Liu, C.; Mach, D. M.; Kalb, C. P.

    2014-12-01

    A passive microwave algorithm for estimating the electrical footprint of charged clouds has been developed and applied to satellite observations taken by the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), which has a domain spanning the entire tropics up to 36 degrees latitude, and compared with lightning-based estimates of global electricity and the Carnegie curve. While these results show considerable agreement with historical observations for convective storms, this method has difficulty characterizing electricity in stratiform clouds and storms at different stages of the convective lifecycle. The algorithm also does not take advantage of the full suite of observations available in the 16-year TRMM dataset, which also includes Precipitation Radar (PR) observations of the structure of storms overflown by the satellite. As a first step towards building an algorithm that can characterize electrical input to the Global Electric Circuit (GEC) from a wide variety of storms across the globe, this study compares passive microwave-based approximations of global electricity with precipitation radar-based approximations in order to determine the relative skill each platform has in describing the "battery" of the GEC and to identify a possible pathway towards a combined metric that can use the strengths of both instruments to better describe electrified clouds.

  2. Estimating the Kernel Mass Ratio in Peanuts Nondestructively Using a Low-Cost Impedance Meter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Earlier, we investigated the possibility of estimating the mass of the kernels in a given volume of unshelled peanuts using a commercial impedance meter. Measurements of impedance and phase angles of peanut samples were made from 1 to 10 MHz at intervals of 1 MHz. The measured values were correlate...

  3. The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation

    PubMed Central

    2016-01-01

    Sivatherium giganteum is an extinct giraffid from the Plio–Pleistocene boundary of the Himalayan foothills. To date, there has been no rigorous skeletal reconstruction of this unusual mammal. Historical and contemporary accounts anecdotally state that Sivatherium rivalled the African elephant in terms of its body mass, but this statement has never been tested. Here, we present a three-dimensional composite skeletal reconstruction and calculate a representative body mass estimate for this species using a volumetric method. We find that the estimated adult body mass of 1246 kg (857—1812 kg range) does not approach that of an African elephant, but confirms that Sivatherium was certainly a large giraffid, and may have been the largest ruminant mammal that has ever existed. We contrast this volumetric estimate with a bivariate scaling estimate derived from Sivatherium's humeral circumference and find that there is a discrepancy between the two. The difference implies that the humeral circumference of Sivatherium is greater than expected for an animal of this size, and we speculate this may be linked to a cranial shift in centre of mass. PMID:26763212

  4. LARGE SCALE EVALUATION OF A PATTERN RECOGNITION/EXPERT SYSTEM FOR MASS SPECTRAL MOLECULAR WEIGHT ESTIMATION

    EPA Science Inventory

    A fast, personal-computer based method of estimating molecular weights of organic compounds from low resolution mass I spectra has been thoroughly evaluated. he method is based on a rule-based pattern,recognition/expert system approach which uses empirical linear corrections whic...

  5. Mass load estimation errors utilizing grab sampling strategies in a karst watershed

    USGS Publications Warehouse

    Fogle, A.W.; Taraba, J.L.; Dinger, J.S.

    2003-01-01

    Developing a mass load estimation method appropriate for a given stream and constituent is difficult due to inconsistencies in hydrologic and constituent characteristics. The difficulty may be increased in flashy flow conditions such as karst. Many projects undertaken are constrained by budget and manpower and do not have the luxury of sophisticated sampling strategies. The objectives of this study were to: (1) examine two grab sampling strategies with varying sampling intervals and determine the error in mass load estimates, and (2) determine the error that can be expected when a grab sample is collected at a time of day when the diurnal variation is most divergent from the daily mean. Results show grab sampling with continuous flow to be a viable data collection method for estimating mass load in the study watershed. Comparing weekly, biweekly, and monthly grab sampling, monthly sampling produces the best results with this method. However, the time of day the sample is collected is important. Failure to account for diurnal variability when collecting a grab sample may produce unacceptable error in mass load estimates. The best time to collect a sample is when the diurnal cycle is nearest the daily mean.

  6. A comparison of approaches for estimating bottom-sediment mass in large reservoirs

    USGS Publications Warehouse

    Juracek, Kyle E.

    2006-01-01

    Estimates of sediment and sediment-associated constituent loads and yields from drainage basins are necessary for the management of reservoir-basin systems to address important issues such as reservoir sedimentation and eutrophication. One method for the estimation of loads and yields requires a determination of the total mass of sediment deposited in a reservoir. This method involves a sediment volume-to-mass conversion using bulk-density information. A comparison of four computational approaches (partition, mean, midpoint, strategic) for using bulk-density information to estimate total bottom-sediment mass in four large reservoirs indicated that the differences among the approaches were not statistically significant. However, the lack of statistical significance may be a result of the small sample size. Compared to the partition approach, which was presumed to provide the most accurate estimates of bottom-sediment mass, the results achieved using the strategic, mean, and midpoint approaches differed by as much as ?4, ?20, and ?44 percent, respectively. It was concluded that the strategic approach may merit further investigation as a less time consuming and less costly alternative to the partition approach.

  7. Measurement Agreement between Estimates of Aerobic Fitness in Youth: The Impact of Body Mass Index

    ERIC Educational Resources Information Center

    Saint-Maurice, Pedro F.; Welk, Gregory J.; Laurson, Kelly R.; Brown, Dale D.

    2014-01-01

    Purpose: The purpose of this study was to examine the impact of body mass index (BMI) on the agreement between aerobic capacity estimates from different Progressive Aerobic Cardiorespiratory Endurance Run (PACER) equations and the Mile Run Test. Method: The agreement between 2 different tests of aerobic capacity was examined on a large data set…

  8. The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation.

    PubMed

    Basu, Christopher; Falkingham, Peter L; Hutchinson, John R

    2016-01-01

    Sivatherium giganteum is an extinct giraffid from the Plio-Pleistocene boundary of the Himalayan foothills. To date, there has been no rigorous skeletal reconstruction of this unusual mammal. Historical and contemporary accounts anecdotally state that Sivatherium rivalled the African elephant in terms of its body mass, but this statement has never been tested. Here, we present a three-dimensional composite skeletal reconstruction and calculate a representative body mass estimate for this species using a volumetric method. We find that the estimated adult body mass of 1246 kg (857-1812 kg range) does not approach that of an African elephant, but confirms that Sivatherium was certainly a large giraffid, and may have been the largest ruminant mammal that has ever existed. We contrast this volumetric estimate with a bivariate scaling estimate derived from Sivatherium's humeral circumference and find that there is a discrepancy between the two. The difference implies that the humeral circumference of Sivatherium is greater than expected for an animal of this size, and we speculate this may be linked to a cranial shift in centre of mass. PMID:26763212

  9. Ratios of the molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil estimated by mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ratios of regioisomers of 72 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lesquerella oil. The ratios of ion signal intensities (or relative abundances) of ...

  10. Ratios of the molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil estimated by mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ratios of regioisomers of 74 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using HPLC and the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lequerella oil. The ratios of relative abundances of the fragment ions fr...

  11. Uranium mass and neutron multiplication factor estimates from time-correlation coincidence counts

    NASA Astrophysics Data System (ADS)

    Xie, Wenxiong; Li, Jiansheng; Zhu, Jianyu

    2015-10-01

    Time-correlation coincidence counts of neutrons are an important means to measure attributes of nuclear material. The main deficiency in the analysis is that an attribute of an unknown component can only be assessed by comparing it with similar known components. There is a lack of a universal method of measurement suitable for the different attributes of the components. This paper presents a new method that uses universal relations to estimate the mass and neutron multiplication factor of any uranium component with known enrichment. Based on numerical simulations and analyses of 64 highly enriched uranium components with different thicknesses and average radii, the relations between mass, multiplication and coincidence spectral features have been obtained by linear regression analysis. To examine the validity of the method in estimating the mass of uranium components with different sizes, shapes, enrichment, and shielding, the features of time-correlation coincidence-count spectra for other objects with similar attributes are simulated. Most of the masses and multiplications for these objects could also be derived by the formulation. Experimental measurements of highly enriched uranium castings have also been used to verify the formulation. The results show that for a well-designed time-dependent coincidence-count measuring system of a uranium attribute, there are a set of relations dependent on the uranium enrichment by which the mass and multiplication of the measured uranium components of any shape and size can be estimated from the features of the source-detector coincidence-count spectrum.

  12. Dynamical Mass Estimates for the Halo of M31 from Keck Spectroscopy

    NASA Astrophysics Data System (ADS)

    Evans, N. Wyn; Wilkinson, Mark I.; Guhathakurta, Puragra; Grebel, Eva K.; Vogt, Steven S.

    2000-09-01

    The last few months have seen the measurements of the radial velocities of all of the dwarf spheroidal companions to the Andromeda galaxy (M31) using the spectrographs (HIRES and LRIS) on the Keck Telescope. This Letter summarizes the data on the radial velocities and distances for all the companion galaxies and presents new dynamical modeling to estimate the mass of the extended halo of M31. The best-fit values for the total mass of M31 are ~(7-10)×1011 Msolar, depending on the details of the modeling. The mass estimate is accompanied by considerable uncertainty caused by the small size of the data set; for example, the upper bound on the total mass is ~24×1011 Msolar, while the lower bound is ~3×1011 Msolar. These values are less than the most recent estimates of the most likely mass of the Milky Way halo. Bearing in mind all the uncertainties, a fair conclusion is that the M31 halo is roughly as massive as that of the Milky Way halo. There is no dynamical evidence for the widely held belief that M31 is more massive-it may even be less massive. Based in part on data collected at W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  13. The Fire INventory from NCAR (FINN): a high resolution global model to estimate the emissions from open burning

    NASA Astrophysics Data System (ADS)

    Wiedinmyer, C.; Akagi, S. K.; Yokelson, R. J.; Emmons, L. K.; Al-Saadi, J. A.; Orlando, J. J.; Soja, A. J.

    2011-07-01

    The Fire INventory from NCAR version 1.0 (FINNv1) provides daily, 1 km resolution, global estimates of the trace gas and particle emissions from open burning of biomass, which includes wildfire, agricultural fires, and prescribed burning and does not include biofuel use and trash burning. Emission factors used in the calculations have been updated with recent data, particularly for the non-methane organic compounds (NMOC). The resulting global annual NMOC emission estimates are as much as a factor of 5 greater than some prior estimates. Chemical speciation profiles, necessary to allocate the total NMOC emission estimates to lumped species for use by chemical transport models, are provided for three widely used chemical mechanisms: SAPRC99, GEOS-CHEM, and MOZART-4. Using these profiles, FINNv1 also provides global estimates of key organic compounds, including formaldehyde and methanol. Uncertainties in the emissions estimates arise from several of the method steps. The use of fire hot spots, assumed area burned, land cover maps, biomass consumption estimates, and emission factors all introduce error into the model estimates. The uncertainty in the FINNv1 emission estimates are about a factor of two; but, the global estimates agree reasonably well with other global inventories of biomass burning emissions for CO, CO2, and other species with less variable emission factors. FINNv1 emission estimates have been developed specifically for modeling atmospheric chemistry and air quality in a consistent framework at scales from local to global. The product is unique because of the high temporal and spatial resolution, global coverage, and the number of species estimated. FINNv1 can be used for both hindcast and forecast or near-real time model applications and the results are being critically evaluated with models and observations whenever possible.

  14. Global estimate of the incidence of clinical pneumonia among children under five years of age.

    PubMed Central

    Rudan, Igor; Tomaskovic, Lana; Boschi-Pinto, Cynthia; Campbell, Harry

    2004-01-01

    OBJECTIVE: Clinical pneumonia (defined as respiratory infections associated with clinical signs of pneumonia, principally pneumonia and bronchiolitis) in children under five years of age is still the leading cause of childhood mortality in the world. In this paper we aim to estimate the worldwide incidence of clinical pneumonia in young children. METHODS: Our estimate for the developing world is based on an analysis of published data on the incidence of clinical pneumonia from community based longitudinal studies. Among more than 2000 studies published since 1961, we identified 46 studies that reported the incidence of clinical pneumonia, and 28 of these met pre-defined quality criteria. FINDINGS: The estimate of the median incidence from those studies was 0.28 episodes per child-year (e/cy). The 25-75% interquartile range was 0.21-0.71. We assessed the plausibility of this estimate using estimates of global mortality from acute respiratory infections and reported case fatality rates for all episodes of clinical pneumonia reported in community-based studies or the case-fatality rate reported only for severe cases and estimates of the proportion of severe cases occurring in a defined population or community. CONCLUSION: The overlap between the ranges of the estimates implies that a plausible incidence estimate of clinical pneumonia for developing countries is 0.29 e/cy. This equates to an annual incidence of 150.7 million new cases, 11-20 million (7-13%) of which are severe enough to require hospital admission. In the developed world no comparable data are available. However, large population-based studies report that the incidence of community-acquired pneumonia among children less than five years old is approximately 0.026 e/cy, suggesting that more than 95% of all episodes of clinical pneumonia in young children worldwide occur in developing countries. PMID:15654403

  15. Bias in GRACE estimates of ice mass change due to accompanying sea-level change

    NASA Astrophysics Data System (ADS)

    Sterenborg, M. G.; Morrow, E.; Mitrovica, J. X.

    2013-04-01

    Observations of spatio-temporal variations in the geopotential using the GRACE satellites have been used to estimate recent mass fluxes from polar ice sheets and glaciers. However, these estimates have not considered the potential bias associated with the migration of water that accompanies the ice melt. This migration is driven by the diminished gravitational attraction of the melting ice reservoir, and this migration, as well as the crustal loading it induces, will contribute to the observed geopotential anomaly. The extent to which this contribution contaminates the ice mass flux estimates depends on how far the smoothing filters applied to the GRACE data extend beyond the ice margins into the ocean. Using the Antarctic Peninsula as a case study, we estimate the magnitude of this bias for a range of melt areas and Gaussian smoothing filter radii. We conclude that GRACE estimates of ice mass loss over the Antarctic Peninsula are systematically overestimating the loss by up to 10 % for filter radii of less than 500 km.

  16. Beyond peak reservoir storage? A global estimate of declining water storage capacity in large reservoirs

    NASA Astrophysics Data System (ADS)

    Wisser, Dominik; Frolking, Steve; Hagen, Stephen; Bierkens, Marc F. P.

    2013-09-01

    Water storage is an important way to cope with temporal variation in water supply and demand. The storage capacity and the lifetime of water storage reservoirs can be significantly reduced by the inflow of sediments. A global, spatially explicit assessment of reservoir storage loss in conjunction with vulnerability to storage loss has not been done. We estimated the loss in reservoir capacity for a global data set of large reservoirs from 1901 to 2010, using modeled sediment flux data. We use spatially explicit population data sets as a proxy for storage demand and calculate storage capacity for all river basins globally. Simulations suggest that the net reservoir capacity is declining as a result of sedimentation (˜5% compared to the installed capacity). Combined with increasing need for storage, these losses challenge the sustainable management of reservoir operation and water resources management in many regions. River basins that are most vulnerable include those with a strong seasonal flow pattern and high population growth rates such as the major river basins in India and China. Decreasing storage capacity globally suggests that the role of reservoir water storage in offsetting sea-level rise is likely weakening and may be changing sign.

  17. Initial estimates of mercury emissions to the atmosphere from global biomass burning.

    PubMed

    Friedli, H R; Arellano, A F; Cinnirella, S; Pirrone, N

    2009-05-15

    The average global annual mercury emission estimate from biomass burning (BMB) for 1997-2006 is 675 +/- 240 Mg/year. This is equivalentto 8% of all currently known anthropogenic and natural mercury emissions. By season, the largest global emissions occur in August and September, the lowest during northern winters. The interannual variability is large and region-specific, and responds to drought conditions. During this particular time period, the largest mercury emissions are from tropical and boreal Asia, followed by Africa and South America. They do not coincide with the largest carbon biomass burning emissions, which originate from Africa. Frequently burning grasslands in Africa and Australia, and agricultural waste burning globally, contribute relatively little to the mercury budget The released mercury from BMB is eventually deposited locally and globally and contributes to the formation of toxic bioaccumulating methyl mercury. Furthermore, increasing temperature in boreal regions, where the largest soil mercury pools reside, is expected to exacerbate mercury emission because of more frequent larger, and more intense fires. PMID:19544847

  18. Effect of GIA models with 3D composite mantle viscosity on GRACE mass balance estimates for Antarctica

    NASA Astrophysics Data System (ADS)

    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

  19. A simplified procedure for mass and stiffness estimation of existing structures

    NASA Astrophysics Data System (ADS)

    Nigro, Antonella; Ditommaso, Rocco; Carlo Ponzo, Felice; Salvatore Nigro, Domenico

    2016-04-01

    This work focuses the attention on a parametric method for mass and stiffness identification of framed structures, based on frequencies evaluation. The assessment of real structures is greatly affected by the consistency of information retrieved on materials and on the influence of both non-structural components and soil. One of the most important matter is the correct definition of the distribution, both in plan and in elevation, of mass and stiffness: depending on concentrated and distributed loads, the presence of infill panels and the distribution of structural elements. In this study modal identification is performed under several mass-modified conditions and structural parameters consistent with the identified modal parameters are determined. Modal parameter identification of a structure before and after the introduction of additional masses is conducted. By considering the relationship between the additional masses and modal properties before and after the mass modification, structural parameters of a damped system, i.e. mass, stiffness and damping coefficient are inversely estimated from these modal parameters variations. The accuracy of the method can be improved by using various mass-modified conditions. The proposed simplified procedure has been tested on both numerical and experimental models by means linear numerical analyses and shaking table tests performed on scaled structures at the Seismic Laboratory of the University of Basilicata (SISLAB). Results confirm the effectiveness of the proposed procedure to estimate masses and stiffness of existing real structures with a maximum error equal to 10%, under the worst conditions. Acknowledgements This study was partially funded by the Italian Civil Protection Department within the project DPC-RELUIS 2015 - RS4 ''Seismic observatory of structures and health monitoring''.

  20. Position Estimation and Local Mapping Using Omnidirectional Images and Global Appearance Descriptors

    PubMed Central

    Berenguer, Yerai; Payá, Luis; Ballesta, Mónica; Reinoso, Oscar

    2015-01-01

    This work presents some methods to create local maps and to estimate the position of a mobile robot, using the global appearance of omnidirectional images. We use a robot that carries an omnidirectional vision system on it. Every omnidirectional image acquired by the robot is described only with one global appearance descriptor, based on the Radon transform. In the work presented in this paper, two different possibilities have been considered. In the first one, we assume the existence of a map previously built composed of omnidirectional images that have been captured from previously-known positions. The purpose in this case consists of estimating the nearest position of the map to the current position of the robot, making use of the visual information acquired by the robot from its current (unknown) position. In the second one, we assume that we have a model of the environment composed of omnidirectional images, but with no information about the location of where the images were acquired. The purpose in this case consists of building a local map and estimating the position of the robot within this map. Both methods are tested with different databases (including virtual and real images) taking into consideration the changes of the position of different objects in the environment, different lighting conditions and occlusions. The results show the effectiveness and the robustness of both methods. PMID:26501289

  1. Position estimation and local mapping using omnidirectional images and global appearance descriptors.

    PubMed

    Berenguer, Yerai; Payá, Luis; Ballesta, Mónica; Reinoso, Oscar

    2015-01-01

    This work presents some methods to create local maps and to estimate the position of a mobile robot, using the global appearance of omnidirectional images. We use a robot that carries an omnidirectional vision system on it. Every omnidirectional image acquired by the robot is described only with one global appearance descriptor, based on the Radon transform. In the work presented in this paper, two different possibilities have been considered. In the first one, we assume the existence of a map previously built composed of omnidirectional images that have been captured from previously-known positions. The purpose in this case consists of estimating the nearest position of the map to the current position of the robot, making use of the visual information acquired by the robot from its current (unknown) position. In the second one, we assume that we have a model of the environment composed of omnidirectional images, but with no information about the location of where the images were acquired. The purpose in this case consists of building a local map and estimating the position of the robot within this map. Both methods are tested with different databases (including virtual and real images) taking into consideration the changes of the position of different objects in the environment, different lighting conditions and occlusions. The results show the effectiveness and the robustness of both methods. PMID:26501289

  2. Temperature-based estimation of global solar radiation using soft computing methodologies

    NASA Astrophysics Data System (ADS)

    Mohammadi, Kasra; Shamshirband, Shahaboddin; Danesh, Amir Seyed; Abdullah, Mohd Shahidan; Zamani, Mazdak

    2015-05-01

    Precise knowledge of solar radiation is indeed essential in different technological and scientific applications of solar energy. Temperature-based estimation of global solar radiation would be appealing owing to broad availability of measured air temperatures. In this study, the potentials of soft computing techniques are evaluated to estimate daily horizontal global solar radiation (DHGSR) from measured maximum, minimum, and average air temperatures (T max, T min, and T avg) in an Iranian city. For this purpose, a comparative evaluation between three methodologies of adaptive neuro-fuzzy inference system (ANFIS), radial basis function support vector regression (SVR-rbf), and polynomial basis function support vector regression (SVR-poly) is performed. Five combinations of T max, T min, and T avg are served as inputs to develop ANFIS, SVR-rbf, and SVR-poly models. The attained results show that all ANFIS, SVR-rbf, and SVR-poly models provide favorable accuracy. Based upon all techniques, the higher accuracies are achieved by models (5) using T max-T min and T max as inputs. According to the statistical results, SVR-rbf outperforms SVR-poly and ANFIS. For SVR-rbf (5), the mean absolute bias error, root mean square error, and correlation coefficient are 1.1931 MJ/m2, 2.0716 MJ/m2, and 0.9380, respectively. The survey results approve that SVR-rbf can be used efficiently to estimate DHGSR from air temperatures.

  3. Temperature-based estimation of global solar radiation using soft computing methodologies

    NASA Astrophysics Data System (ADS)

    Mohammadi, Kasra; Shamshirband, Shahaboddin; Danesh, Amir Seyed; Abdullah, Mohd Shahidan; Zamani, Mazdak

    2016-07-01

    Precise knowledge of solar radiation is indeed essential in different technological and scientific applications of solar energy. Temperature-based estimation of global solar radiation would be appealing owing to broad availability of measured air temperatures. In this study, the potentials of soft computing techniques are evaluated to estimate daily horizontal global solar radiation (DHGSR) from measured maximum, minimum, and average air temperatures ( T max, T min, and T avg) in an Iranian city. For this purpose, a comparative evaluation between three methodologies of adaptive neuro-fuzzy inference system (ANFIS), radial basis function support vector regression (SVR-rbf), and polynomial basis function support vector regression (SVR-poly) is performed. Five combinations of T max, T min, and T avg are served as inputs to develop ANFIS, SVR-rbf, and SVR-poly models. The attained results show that all ANFIS, SVR-rbf, and SVR-poly models provide favorable accuracy. Based upon all techniques, the higher accuracies are achieved by models (5) using T max- T min and T max as inputs. According to the statistical results, SVR-rbf outperforms SVR-poly and ANFIS. For SVR-rbf (5), the mean absolute bias error, root mean square error, and correlation coefficient are 1.1931 MJ/m2, 2.0716 MJ/m2, and 0.9380, respectively. The survey results approve that SVR-rbf can be used efficiently to estimate DHGSR from air temperatures.

  4. Plate Motion and Crustal Deformation Estimated with Geodetic Data from the Global Positioning System

    NASA Technical Reports Server (NTRS)

    Argus, Donald F.; Heflin, Michael B.

    1995-01-01

    We use geodetic data taken over four years with the Global Positioning System (GPS) to estimate: (1) motion between six major plates and (2) motion relative to these plates of ten sites in plate boundary zones. The degree of consistency between geodetic velocities and rigid plates requires the (one-dimensional) standard errors in horizontal velocities to be approx. 2 mm/yr. Each of the 15 angular velocities describing motion between plate pairs that we estimate with GPS differs insignificantly from the corresponding angular velocity in global plate motion model NUVEL-1A, which averages motion over the past 3 m.y. The motion of the Pacific plate relative to both the Eurasian and North American plates is observed to be faster than predicted by NUVEL-1A, supporting the inference from Very Long B ase- line Interferometry (VLBI) that motion of the Pacific plate has speed up over the past few m.y. The Eurasia-North America pole of rotation is estimated to be north of NUVEL-1A, consistent with the independent hypothesis that the pole has recently migrated northward across northeast Asia to near the Lena River delta. Victoria, which lies above the main thrust at the Cascadia subduction zone, moves relative to the interior of the overriding plate at 30% of the velocity of the subducting plate, reinforcing the conclusion that the thrust there is locked beneath the continental shelf and slope.

  5. Estimating shaking-induced casualties and building damage for global earthquake events: a proposed modelling approach

    USGS Publications Warehouse

    So, Emily; Spence, Robin

    2013-01-01

    Recent earthquakes such as the Haiti earthquake of 12 January 2010 and the Qinghai earthquake on 14 April 2010 have highlighted the importance of rapid estimation of casualties after the event for humanitarian response. Both of these events resulted in surprisingly high death tolls, casualties and survivors made homeless. In the Mw = 7.0 Haiti earthquake, over 200,000 people perished with more than 300,000 reported injuries and 2 million made homeless. The Mw = 6.9 earthquake in Qinghai resulted in over 2,000 deaths with a further 11,000 people with serious or moderate injuries and 100,000 people have been left homeless in this mountainous region of China. In such events relief efforts can be significantly benefitted by the availability of rapid estimation and mapping of expected casualties. This paper contributes to ongoing global efforts to estimate probable earthquake casualties very rapidly after an earthquake has taken place. The analysis uses the assembled empirical damage and casualty data in the Cambridge Earthquake Impacts Database (CEQID) and explores data by event and across events to test the relationships of building and fatality distributions to the main explanatory variables of building type, building damage level and earthquake intensity. The prototype global casualty estimation model described here uses a semi-empirical approach that estimates damage rates for different classes of buildings present in the local building stock, and then relates fatality rates to the damage rates of each class of buildings. This approach accounts for the effect of the very different types of buildings (by climatic zone, urban or rural location, culture, income level etc), on casualties. The resulting casualty parameters were tested against the overall casualty data from several historical earthquakes in CEQID; a reasonable fit was found.

  6. Estimating luminosities and stellar masses of galaxies photometrically without determining redshifts

    SciTech Connect

    Hsieh, B. C.; Yee, H. K. C. E-mail: hyee@astro.utoronto.ca

    2014-09-10

    Large direct imaging surveys usually use a template-fitting technique to estimate photometric redshifts for galaxies, which are then applied to derive important galaxy properties such as luminosities and stellar masses. These estimates can be noisy and suffer from systematic biases because of the possible mis-selection of templates and the propagation of the photometric redshift uncertainty. We introduce an algorithm, the Direct Empirical Photometric method (DEmP), that can be used to directly estimate these quantities using training sets, bypassing photometric redshift determination. DEmP also applies two techniques to minimize the effects arising from the non-uniform distribution of training set galaxy redshifts from a flux-limited sample. First, for each input galaxy, fitting is performed using a subset of the training set galaxies with photometry and colors closest to those of the input galaxy. Second, the training set is artificially resampled to produce a flat distribution in redshift or other properties, e.g., luminosity. To test the performance of DEmP, we use a four filter-band mock catalog to examine its ability to recover redshift, luminosity, stellar mass, and luminosity and stellar mass functions. We also compare the results to those from two publicly available template-fitting methods, finding that the DEmP algorithm outperforms both. We find that resampling the training set to have a uniform redshift distribution produces the best results not only in photometric redshift, but also in estimating luminosity and stellar mass. The DEmP method is especially powerful in estimating quantities such as near-IR luminosities and stellar mass using only data from a small number of optical bands.

  7. Body mass estimation in xenarthra: a predictive equation suitable for all quadrupedal terrestrial placentals?

    PubMed

    De Esteban-Trivigno, Soledad; Mendoza, Manuel; De Renzi, Miquel

    2008-10-01

    The Magnorder Xenarthra includes strange extinct groups, like glyptodonts, similar to large armadillos, and ground sloths, terrestrial relatives of the extant tree sloths. They have created considerable paleobiological interest in the last decades; however, the ecology of most of these species is still controversial or unknown. The body mass estimation of extinct species has great importance for paleobiological reconstructions. The commonest way to estimate body mass from fossils is through linear regression. However, if the studied species does not have similar extant relatives, the allometric pattern described by the regression could differ from those shown by the extinct group. That is the case for glyptodonts and ground sloths. Thus, stepwise multiple regression were developed including extant xenarthrans (their taxonomic relatives) and ungulates (their size and ecological relatives). Cases were weighted to maximize the taxonomic evenness. Twenty-eight equations were obtained. The distribution of the percent of prediction error (%PE) was analyzed between taxonomic groups (Perissodactyla, Artiodactyla, and Xenarthra) and size groups (0-20 kg, 20-300 kg, and more than 300 kg). To assess the predictive power of the functions, equations were applied to species not included in the regression development [test set cross validation, (TSCV)]. Only five equations had a homogeneous %PE between the aforementioned groups. These were applied to five extinct species. A mean body mass of 80 kg was estimated for Propalaehoplophorus australis (Cingulata: Glyptodontidae), 594 kg for Scelidotherium leptocephalum (Phyllophaga: Mylodontidae), and 3,550.7 kg for Lestodon armatus (Phyllophaga: Mylodontidae). The high scatter of the body mass estimations obtained for Catonyx tarijensis (Phyllophaga: Mylodontidae) and Thalassocnus natans (Phyllophaga: Megatheriidae), probably due to different specializations, prevented us from predicting its body mass. Surprisingly, although obtained

  8. Double-observer approach to estimating egg mass abundance of vernal pool breeding amphibians

    USGS Publications Warehouse

    Grant, E.H.C.; Jung, R.E.; Nichols, J.D.; Hines, J.E.

    2005-01-01

    Interest in seasonally flooded pools, and the status of associated amphibian populations, has initiated programs in the northeastern United States to document and monitor these habitats. Counting egg masses is an effective way to determine the population size of pool-breeding amphibians, such as wood frogs (Rana sylvatica) and spotted salamanders (Ambystoma maculatum). However, bias is associated with counts if egg masses are missed. Counts unadjusted for the proportion missed (i.e., without adjustment for detection probability) could lead to false assessments of population trends. We used a dependent double-observer method in 2002-2003 to estimate numbers of wood frog and spotted salamander egg masses at seasonal forest pools in 13 National Wildlife Refuges, 1 National Park, 1 National Seashore, and 1 State Park in the northeastern United States. We calculated detection probabilities for egg masses and examined whether detection probabilities varied by species, observers, pools, and in relation to pool characteristics (pool area, pool maximum depth, within-pool vegetation). For the 2 years, model selection indicated that no consistent set of variables explained the variation in data sets from individual Refuges and Parks. Because our results indicated that egg mass detection probabilities vary spatially and temporally, we conclude that it is essential to use estimation procedures, such as double-observer methods with egg mass surveys, to determine population sizes and trends of these species.

  9. X-ray dual energy spectral parameter optimization for bone Calcium/Phosphorus mass ratio estimation

    NASA Astrophysics Data System (ADS)

    Sotiropoulou, P. I.; Fountos, G. P.; Martini, N. D.; Koukou, V. N.; Michail, C. M.; Valais, I. G.; Kandarakis, I. S.; Nikiforidis, G. C.

    2015-09-01

    Calcium (Ca) and Phosphorus (P) bone mass ratio has been identified as an important, yet underutilized, risk factor in osteoporosis diagnosis. The purpose of this simulation study is to investigate the use of effective or mean mass attenuation coefficient in Ca/P mass ratio estimation with the use of a dual-energy method. The investigation was based on the minimization of the accuracy of Ca/P ratio, with respect to the Coefficient of Variation of the ratio. Different set-ups were examined, based on the K-edge filtering technique and single X-ray exposure. The modified X-ray output was attenuated by various Ca/P mass ratios resulting in nine calibration points, while keeping constant the total bone thickness. The simulated data were obtained considering a photon counting energy discriminating detector. The standard deviation of the residuals was used to compare and evaluate the accuracy between the different dual energy set-ups. The optimum mass attenuation coefficient for the Ca/P mass ratio estimation was the effective coefficient in all the examined set-ups. The variation of the residuals between the different set-ups was not significant.

  10. An advanced shape-fitting algorithm applied to quadrupedal mammals: improving volumetric mass estimates

    PubMed Central

    Brassey, Charlotte A.; Gardiner, James D.

    2015-01-01

    Body mass is a fundamental physical property of an individual and has enormous bearing upon ecology and physiology. Generating reliable estimates for body mass is therefore a necessary step in many palaeontological studies. Whilst early reconstructions of mass in extinct species relied upon isolated skeletal elements, volumetric techniques are increasingly applied to fossils when skeletal completeness allows. We apply a new ‘alpha shapes’ (α-shapes) algorithm to volumetric mass estimation in quadrupedal mammals. α-shapes are defined by: (i) the underlying skeletal structure to which they are fitted; and (ii) the value α, determining the refinement of fit. For a given skeleton, a range of α-shapes may be fitted around the individual, spanning from very coarse to very fine. We fit α-shapes to three-dimensional models of extant mammals and calculate volumes, which are regressed against mass to generate predictive equations. Our optimal model is characterized by a high correlation coefficient and mean square error (r2=0.975, m.s.e.=0.025). When applied to the woolly mammoth (Mammuthus primigenius) and giant ground sloth (Megatherium americanum), we reconstruct masses of 3635 and 3706 kg, respectively. We consider α-shapes an improvement upon previous techniques as resulting volumes are less sensitive to uncertainties in skeletal reconstructions, and do not require manual separation of body segments from skeletons. PMID:26361559

  11. ARE OUTFLOWS BIASING SINGLE-EPOCH C IV BLACK HOLE MASS ESTIMATES?

    SciTech Connect

    Denney, K. D.

    2012-11-01

    We use a combination of reverberation mapping data and single-epoch (SE) spectra of the C IV emission line in a sample of both low- and high-redshift active galactic nuclei to investigate sources of the discrepancies between C IV- and H{beta}-based SE black hole (BH) mass estimates. We find that for all reverberation mapped sources, there is a component of the line profile that does not reverberate, and the velocity characteristics of this component vary from object to object. The differing strength and properties of this non-variable component are responsible for much of the scatter in C IV-based BH masses compared to H{beta} masses. The C IV mass bias introduced by this non-variable component is correlated with the shape of the C IV line, allowing us to make an empirical correction to the BH mass estimates. Using this correction and accounting for other sources of scatter, such as poor data quality and data inhomogeneity, reduces the scatter between the C IV and H{beta} masses in our sample by a factor of {approx}2, to only {approx}0.2 dex. We discuss the possibility that this non-variable C IV component originates in an orientation-dependent outflow from either the proposed broad-line region disk wind or the intermediate-line region, a high-velocity inner extension of the narrow-line region.

  12. Global distribution of soil organic carbon, based on the Harmonized World Soil Database - Part 1: Masses and frequency distribution of SOC stocks for the tropics, permafrost regions, wetlands, and the world

    NASA Astrophysics Data System (ADS)

    Köchy, M.; Hiederer, R.; Freibauer, A.

    2014-09-01

    The global soil organic carbon (SOC) mass is relevant for the carbon cycle budget. We review current estimates of soil organic carbon stocks (mass/area) and mass (stock × area) in wetlands, permafrost and tropical regions and the world in the upper 1 m of soil. The Harmonized World Soil Database (HWSD) v.1.2 provides one of the most recent and coherent global data sets of SOC, giving a total mass of 2476 Pg. Correcting the HWSD's bulk density of organic soils, especially Histosols, results in a mass of 1062 Pg. The uncertainty of bulk density of Histosols alone introduces a range of -56 to +180 Pg for the estimate of global SOC in the top 1 m, larger than estimates of global soil respiration. We report the spatial distribution of SOC stocks per 0.5 arc minutes, the areal masses of SOC and the quantiles of SOC stocks by continents, wetland types, and permafrost types. Depending on the definition of "wetland", wetland soils contain between 82 and 158 Pg SOC. Incorporating more detailed estimates for permafrost from the Northern Circumpolar Soil Carbon Data Base (496 Pg SOC) and tropical peatland carbon, global soils contain 1324 Pg SOC in the upper 1 m including 421 Pg in tropical soils, whereof 40 Pg occur in tropical wetlands. Global SOC amounts to just under 3000 Pg when estimates for deeper soil layers are included. Variability in estimates is due to variation in definitions of soil units, differences in soil property databases, scarcity of information about soil carbon at depths > 1 m in peatlands, and variation in definitions of "peatland".

  13. Late Frasnian mass extinction: Conodont event stratigraphy, global changes, and possible causes

    NASA Technical Reports Server (NTRS)

    Sandberg, Charles A.; Ziegler, Willi; Dreesen, Roland; Butler, Jamie L.

    1988-01-01

    Several abrupt changes in conodont biofacies are documented to occur synchronously at six primary control sections across the Frasnian-Famennian boundary in Euramerica. These changes occurred within a time-span of only about 100,000 years near the end of the latest Frasnian linguiformis Zone, which is formally named to replace the Uppermost gigas Zone. The conodont-biofacies changes are interpreted to reflect a eustatic rise followed by an abrupt eustatic fall immediately preceding the late Frasnian mass extinction. Two new conodont species are named and described. Ancyrognathus ubiquitus n.sp. is recorded only just below and above the level of late Frasnian extinction and hence is a global marker for that event. Palmatolepispraetriangularis n.sp. is the long-sought Frasnian ancestor of the formerly cryptogenic species, Pa. triangularis, indicator of the earliest Famennian Lower triangularis Zone. The actual extinction event occurred entirely within the Frasnian and is interpreted to have been of brief duration-from as long as 20,000 years to as short as several days. The eustatic rise-and-fall couplet associated with the late Frasnian mass extinction is similar to eustatic couplets associated with the demise of most Frasnian (F2h) reefs worldwide about 1 m.y. earlier and with a latest Famennian mass extinction about 9.5 m.y. later. All these events may be directly or indirectly attributable to extraterrestrial triggering mechanisms. An impact of a small bolide or a near miss of a larger bolide may have caused the earlier demise of Frasnian reefs. An impact of possibly the same larger bolide in the Southern Hemisphere would explain the late Frasnian mass extinction. Global regression during the Famennian probably resulted from Southern-Hemisphere glaciation triggered by the latest Frasnian impact. Glaciation probably was the indirect cause of the latest Famennian mass extinction.

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

    NASA Technical Reports Server (NTRS)

    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

  15. Science and User Needs for Observing Global Mass Transport to Understand Global Change and to Benefit Society

    NASA Astrophysics Data System (ADS)

    Pail, Roland; Bingham, Rory; Braitenberg, Carla; Dobslaw, Henryk; Eicker, Annette; Güntner, Andreas; Horwath, Martin; Ivins, Eric; Longuevergne, Laurent; Panet, Isabelle; Wouters, Bert

    2015-11-01

    Satellite gravimetry is a unique measurement technique for observing mass transport processes in the Earth system on a global scale, providing essential indicators of both subtle and dramatic global change. Although past and current satellite gravity missions have achieved spectacular science results, due to their limited spatial and temporal resolution as well as limited length of the available time series numerous important questions are still unresolved. Therefore, it is important to move from current demonstration capabilities to sustained observation of the Earth's gravity field. In an international initiative performed under the umbrella of the International Union of Geodesy and Geophysics, consensus on the science and user needs for a future satellite gravity observing system has been derived by an international panel of scientists representing the main fields of application, i.e., continental hydrology, cryosphere, ocean, atmosphere and solid Earth. In this paper the main results and findings of this initiative are summarized. The required target performance in terms of equivalent water height has been identified as 5 cm for monthly fields and 0.5 cm/year for long-term trends at a spatial resolution of 150 km. The benefits to meet the main scientific and societal objectives are investigated, and the added value is demonstrated for selected case studies covering the main fields of application. The resulting consolidated view on the required performance of a future sustained satellite gravity observing system represents a solid basis for the definition of technological and mission requirements, and is a prerequisite for mission design studies of future mission concepts and constellations.

  16. Africa-wide water balance estimation using remote sensing and global weather datasets

    NASA Astrophysics Data System (ADS)

    Senay, G. B.; Pengra, B.; Bohms, S.; Singh, A.; Verdin, J. P.

    2010-12-01

    The continent of Africa encompasses diverse ecological systems - from desert to equatorial forest - with major rivers flowing in different directions such as the Congo, Niger, Nile, Senegal and Zambezi. A lack of consistent data or access to important data sets such as rainfall, stream flow and evapotranspiration has been a barrier to developing Africa-wide water atlas in the past. We used globally available and consistent weather and remotely sensed datasets to estimate annual average (2001-2009) actual evapotranspiration (ET) at 1 km scale for the entire continent from the 8-day ET estimates using the Simplified Surface Energy Balance (SSEB) model. Thermal and optical remotely sensed data from the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor were used. Annual rainfall was generated from the widely used climatological monthly rainfall summaries developed by FAO (1961-1990) at 10 km resolution. Spatially explicit annual water balance was calculated as the difference between annual rainfall and actual ET at 1 km resolution. The result was summarized by major river basins to estimate the relative contribution of the riparian countries in the basin. From this study, we estimated the total annual runoff depth for Africa to be a depth of 142.5 mm or 4,483 km3 (using a continental area of 30.65 km2). This figure compares within 4 percent of an average runoff estimate reported in the literature.

  17. Estimating the sources of global sea level rise with data assimilation techniques

    PubMed Central

    Hay, Carling C.; Morrow, Eric; Kopp, Robert E.; Mitrovica, Jerry X.

    2013-01-01

    A rapidly melting ice sheet produces a distinctive geometry, or fingerprint, of sea level (SL) change. Thus, a network of SL observations may, in principle, be used to infer sources of meltwater flux. We outline a formalism, based on a modified Kalman smoother, for using tide gauge observations to estimate the individual sources of global SL change. We also report on a series of detection experiments based on synthetic SL data that explore the feasibility of extracting source information from SL records. The Kalman smoother technique iteratively calculates the maximum-likelihood estimate of Greenland ice sheet (GIS) and West Antarctic ice sheet (WAIS) melt at each time step, and it accommodates data gaps while also permitting the estimation of nonlinear trends. Our synthetic tests indicate that when all tide gauge records are used in the analysis, it should be possible to estimate GIS and WAIS melt rates greater than ∼0.3 and ∼0.4 mm of equivalent eustatic sea level rise per year, respectively. We have also implemented a multimodel Kalman filter that allows us to account rigorously for additional contributions to SL changes and their associated uncertainty. The multimodel filter uses 72 glacial isostatic adjustment models and 3 ocean dynamic models to estimate the most likely models for these processes given the synthetic observations. We conclude that our modified Kalman smoother procedure provides a powerful method for inferring melt rates in a warming world. PMID:22543163

  18. Estimating the sources of global sea level rise with data assimilation techniques

    NASA Astrophysics Data System (ADS)

    Hay, Carling C.; Morrow, Eric; Kopp, Robert E.; Mitrovica, Jerry X.

    2013-02-01

    A rapidly melting ice sheet produces a distinctive geometry, or fingerprint, of sea level (SL) change. Thus, a network of SL observations may, in principle, be used to infer sources of meltwater flux. We outline a formalism, based on a modified Kalman smoother, for using tide gauge observations to estimate the individual sources of global SL change. We also report on a series of detection experiments based on synthetic SL data that explore the feasibility of extracting source information from SL records. The Kalman smoother technique iteratively calculates the maximum-likelihood estimate of Greenland ice sheet (GIS) and West Antarctic ice sheet (WAIS) melt at each time step, and it accommodates data gaps while also permitting the estimation of nonlinear trends. Our synthetic tests indicate that when all tide gauge records are used in the analysis, it should be possible to estimate GIS and WAIS melt rates greater than ∼0.3 and ∼0.4 mm of equivalent eustatic sea level rise per year, respectively. We have also implemented a multimodel Kalman filter that allows us to account rigorously for additional contributions to SL changes and their associated uncertainty. The multimodel filter uses 72 glacial isostatic adjustment models and 3 ocean dynamic models to estimate the most likely models for these processes given the synthetic observations. We conclude that our modified Kalman smoother procedure provides a powerful method for inferring melt rates in a warming world.

  19. Oceanic primary production: 2. Estimation at global scale from satellite (coastal zone color scanner) chlorophyll

    SciTech Connect

    Antione, D.; Andre, J.M.; Morel, A.

    1996-03-01

    The purpose of this study was to assess the oceanic seasonal evolution and spatial distribution of photosynthetic carbon fixation. Computation of primary production from the upper ocean chlorophyll-like pigment concentrations were made from monthly global maps from the coastal zone color scanner data archive. Relative contributions of various oceans and zonal belts were identified. Depending on the ratio used for active pigments to total pigments, the calculated global annual production ranges from 36.5 and 45.6 G tons (metric) carbon per year. These values are among the highest estimates proposed to date; although the absolute values may be somewhat questionable, the relative contribution of the various zonal belts and oceans are considered to have a high degree of accuracy. 33 refs., 4 figs., 2 tabs.

  20. Estimation of daily global solar radiation as a function of routine meteorological data in Mediterranean areas

    NASA Astrophysics Data System (ADS)

    Meza, Francisco Javier; Yebra, María Lorenzo

    2016-08-01

    Solar radiation is the main responsible of many processes of the biophysical environment. Temperature changes, snow melt dynamics, carbon sequestration, evaporation from soils, plants, and open water bodies are explained by the amount of radiation received in a surface. Lack of direct observations and insufficient record length limit the ability to use global solar radiation information for resource use management and planning. Based on the general equation of Bristow and Campbell, we propose a modification that allows us to better represent atmospheric transmissivity as a function of routine meteorological variables and improve estimates of global solar radiation in Mediterranean and semi arid areas. The improved Bristow-Campbell model (IBC) is easy to use in any location where measurements of temperature, precipitation, and relative humidity are available, and present a simple solution that can be used as proxy for relative humidity in case that variable is not been measured.

  1. Estimation of daily global solar radiation as a function of routine meteorological data in Mediterranean areas

    NASA Astrophysics Data System (ADS)

    Meza, Francisco Javier; Yebra, María Lorenzo

    2015-06-01

    Solar radiation is the main responsible of many processes of the biophysical environment. Temperature changes, snow melt dynamics, carbon sequestration, evaporation from soils, plants, and open water bodies are explained by the amount of radiation received in a surface. Lack of direct observations and insufficient record length limit the ability to use global solar radiation information for resource use management and planning. Based on the general equation of Bristow and Campbell, we propose a modification that allows us to better represent atmospheric transmissivity as a function of routine meteorological variables and improve estimates of global solar radiation in Mediterranean and semi arid areas. The improved Bristow-Campbell model (IBC) is easy to use in any location where measurements of temperature, precipitation, and relative humidity are available, and present a simple solution that can be used as proxy for relative humidity in case that variable is not been measured.

  2. Using Machine Learning to Estimate Global PM2.5 for Environmental Health Studies

    PubMed Central

    Lary, D. J.; Lary, T.; Sattler, B.

    2015-01-01

    With the increasing awareness of health impacts of particulate matter, there is a growing need to comprehend the spatial and temporal variations of the global abundance of ground-level airborne particulate matter (PM2.5). Here we use a suite of remote sensing and meteorological data products together with ground based observations of PM2.5 from 8,329 measurement sites in 55 countries taken between 1997 and 2014 to train a machine learning algorithm to estimate the daily distributions of PM2.5 from 1997 to the present. We demonstrate that the new PM2.5 data product can reliably represent global observations of PM2.5 for epidemiological studies. An analysis of Baltimore schizophrenia emergency room admissions is presented in terms of the levels of ambient pollution. PM2.5 appears to have an impact on some aspects of mental health. PMID:26005352

  3. Global and regional estimates of COPD prevalence: Systematic review and meta–analysis

    PubMed Central

    Adeloye, Davies; Chua, Stephen; Lee, Chinwei; Basquill, Catriona; Papana, Angeliki; Theodoratou, Evropi; Nair, Harish; Gasevic, Danijela; Sridhar, Devi; Campbell, Harry; Chan, Kit Yee; Sheikh, Aziz; Rudan, Igor

    2015-01-01

    Background The burden of chronic obstructive pulmonary disease (COPD) across many world regions is high. We aim to estimate COPD prevalence and number of disease cases for the years 1990 and 2010 across world regions based on the best available evidence in publicly accessible scientific databases. Methods We conducted a systematic search of Medline, EMBASE and Global Health for original, population–based studies providing spirometry–based prevalence rates of COPD across the world from January 1990 to December 2014. Random effects meta–analysis was conducted on extracted crude prevalence rates of COPD, with overall summaries of the meta–estimates (and confidence intervals) reported separately for World Health Organization (WHO) regions, the World Bank's income categories and settings (urban and rural). We developed a meta–regression epidemiological model that we used to estimate the prevalence of COPD in people aged 30 years or more. Findings Our search returned 37 472 publications. A total of 123 studies based on a spirometry–defined prevalence were retained for the review. From the meta–regression epidemiological model, we estimated about 227.3 million COPD cases in the year 1990 among people aged 30 years or more, corresponding to a global prevalence of 10.7% (95% confidence interval (CI) 7.3%–14.0%) in this age group. The number of COPD cases increased to 384 million in 2010, with a global prevalence of 11.7% (8.4%–15.0%). This increase of 68.9% was mainly driven by global demographic changes. Across WHO regions, the highest prevalence was estimated in the Americas (13.3% in 1990 and 15.2% in 2010), and the lowest in South East Asia (7.9% in 1990 and 9.7% in 2010). The percentage increase in COPD cases between 1990 and 2010 was the highest in the Eastern Mediterranean region (118.7%), followed by the African region (102.1%), while the European region recorded the lowest increase (22.5%). In 1990, we estimated about 120.9 million COPD cases

  4. RETIRED A STARS: THE EFFECT OF STELLAR EVOLUTION ON THE MASS ESTIMATES OF SUBGIANTS

    SciTech Connect

    Johnson, John Asher; Morton, Timothy D.; Wright, Jason T.

    2013-01-20

    Doppler surveys have shown that the occurrence rate of Jupiter-mass planets appears to increase as a function of stellar mass. However, this result depends on the ability to accurately measure the masses of evolved stars. Recently, Lloyd called into question the masses of subgiant stars targeted by Doppler surveys. Lloyd argues that very few observable subgiants have masses greater than 1.5 M {sub Sun }, and that most of them have masses in the range 1.0-1.2 M {sub Sun }. To investigate this claim, we use Galactic stellar population models to generate an all-sky distribution of stars. We incorporate the effects that make massive subgiants less numerous, such as the initial mass function and differences in stellar evolution timescales. We find that these effects lead to negligibly small systematic errors in stellar mass estimates, in contrast to the Almost-Equal-To 50% errors predicted by Lloyd. Additionally, our simulated target sample does in fact include a significant fraction of stars with masses greater than 1.5 M {sub Sun }, primarily because the inclusion of an apparent magnitude limit results in a Malmquist-like bias toward more massive stars, in contrast to the volume-limited simulations of Lloyd. The magnitude limit shifts the mean of our simulated distribution toward higher masses and results in a relatively smaller number of evolved stars with masses in the range 1.0-1.2 M {sub Sun }. We conclude that, within the context of our present-day understanding of stellar structure and evolution, many of the subgiants observed in Doppler surveys are indeed as massive as main-sequence A stars.

  5. Complementary information from TRMM and CloudSat to improve our global estimate of precipitation

    NASA Astrophysics Data System (ADS)

    Behrangi, A.; Stephens, G. L.; Adler, R. F.; Huffman, G. J.; Lambrigtsen, B.; Lebsock, M. D.

    2013-12-01

    Complementary information from CloudSat Cloud Profiling Radar (CPR), TRMM PR, and AMSR-E are used to investigate the precipitation detection and estimation performance of a suite of precipitation measuring sensors, commonly used in the production of the merged precipitation products. CPR has high sensitivity to liquid and frozen hydrometeors and can provide added information with respect to the measurement of light rain and snowfall within 80oS-80oN. PR has also enabled significant advancement in quantification of moderate to intense rainfall. The study requires careful consideration of the scale issues among different sensors that will be discussed. Furthermore, we expand the sensor-level analysis to investigate the performance of the global precipitation climatology products: GPCP and CMAP. CloudSat together with TRMM and AMSR-E are used to calculate the mean global precipitation rate and its zonal distribution through a merging process constrained by precipitation occurrence from CloudSat. The three sensors have not been used in GPCP and CMAP thus give us an independent estimate of global precipitation and can be used to understand and assess the strengths and potential weaknesses of the two products. The insights gained from the analysis are found extremely useful to guide our future updates of the products as well as to design future precipitation measuring sensors. The study highlights the important role of GPM to better detect and quantify global precipitation using its Ka/Ku band dual frequency precipitation radar (DPR) and multichannel passive microwave imager (GMI).

  6. Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty

    DOE PAGESBeta

    Ballantyne, A. P.; Andres, R.; Houghton, R.; Stocker, B. D.; Wanninkhof, R.; Anderegg, W.; Cooper, L. A.; DeGrandpre, M.; Tans, P. P.; Miller, J. B.; et al

    2015-04-30

    Over the last 5 decades monitoring systems have been developed to detect changes in the accumulation of carbon (C) in the atmosphere and ocean; however, our ability to detect changes in the behavior of the global C cycle is still hindered by measurement and estimate errors. Here we present a rigorous and flexible framework for assessing the temporal and spatial components of estimate errors and their impact on uncertainty in net C uptake by the biosphere. We present a novel approach for incorporating temporally correlated random error into the error structure of emission estimates. Based on this approach, we concludemore » that the 2σ uncertainties of the atmospheric growth rate have decreased from 1.2 Pg C yr₋1 in the 1960s to 0.3 Pg C yr₋1 in the 2000s due to an expansion of the atmospheric observation network. The 2σ uncertainties in fossil fuel emissions have increased from 0.3 Pg C yr₋1 in the 1960s to almost 1.0 Pg C yr₋1 during the 2000s due to differences in national reporting errors and differences in energy inventories. Lastly, while land use emissions have remained fairly constant, their errors still remain high and thus their global C uptake uncertainty is not trivial. Currently, the absolute errors in fossil fuel emissions rival the total emissions from land use, highlighting the extent to which fossil fuels dominate the global C budget. Because errors in the atmospheric growth rate have decreased faster than errors in total emissions have increased, a ~20% reduction in the overall uncertainty of net C global uptake has occurred. Given all the major sources of error in the global C budget that we could identify, we are 93% confident that terrestrial C uptake has increased and 97% confident that ocean C uptake has increased over the last 5 decades. Thus, it is clear that arguably one of the most vital ecosystem services currently provided by the biosphere is the continued removal of approximately half of atmospheric CO2 emissions from the

  7. Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty

    NASA Astrophysics Data System (ADS)

    Ballantyne, A. P.; Andres, R.; Houghton, R.; Stocker, B. D.; Wanninkhof, R.; Anderegg, W.; Cooper, L. A.; DeGrandpre, M.; Tans, P. P.; Miller, J. B.; Alden, C.; White, J. W. C.

    2015-04-01

    Over the last 5 decades monitoring systems have been developed to detect changes in the accumulation of carbon (C) in the atmosphere and ocean; however, our ability to detect changes in the behavior of the global C cycle is still hindered by measurement and estimate errors. Here we present a rigorous and flexible framework for assessing the temporal and spatial components of estimate errors and their impact on uncertainty in net C uptake by the biosphere. We present a novel approach for incorporating temporally correlated random error into the error structure of emission estimates. Based on this approach, we conclude that the 2σ uncertainties of the atmospheric growth rate have decreased from 1.2 Pg C yr-1 in the 1960s to 0.3 Pg C yr-1 in the 2000s due to an expansion of the atmospheric observation network. The 2σ uncertainties in fossil fuel emissions have increased from 0.3 Pg C yr-1 in the 1960s to almost 1.0 Pg C yr-1 during the 2000s due to differences in national reporting errors and differences in energy inventories. Lastly, while land use emissions have remained fairly constant, their errors still remain high and thus their global C uptake uncertainty is not trivial. Currently, the absolute errors in fossil fuel emissions rival the total emissions from land use, highlighting the extent to which fossil fuels dominate the global C budget. Because errors in the atmospheric growth rate have decreased faster than errors in total emissions have increased, a ~20% reduction in the overall uncertainty of net C global uptake has occurred. Given all the major sources of error in the global C budget that we could identify, we are 93% confident that terrestrial C uptake has increased and 97% confident that ocean C uptake has increased over the last 5 decades. Thus, it is clear that arguably one of the most vital ecosystem services currently provided by the biosphere is the continued removal of approximately half of atmospheric CO2 emissions from the atmosphere

  8. Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty

    SciTech Connect

    Ballantyne, A. P.; Andres, R.; Houghton, R.; Stocker, B. D.; Wanninkhof, R.; Anderegg, W.; Cooper, L. A.; DeGrandpre, M.; Tans, P. P.; Miller, J. B.; Alden, C.; White, J. W. C.

    2015-04-30

    Over the last 5 decades monitoring systems have been developed to detect changes in the accumulation of carbon (C) in the atmosphere and ocean; however, our ability to detect changes in the behavior of the global C cycle is still hindered by measurement and estimate errors. Here we present a rigorous and flexible framework for assessing the temporal and spatial components of estimate errors and their impact on uncertainty in net C uptake by the biosphere. We present a novel approach for incorporating temporally correlated random error into the error structure of emission estimates. Based on this approach, we conclude that the 2σ uncertainties of the atmospheric growth rate have decreased from 1.2 Pg C yr₋1 in the 1960s to 0.3 Pg C yr₋1 in the 2000s due to an expansion of the atmospheric observation network. The 2σ uncertainties in fossil fuel emissions have increased from 0.3 Pg C yr₋1 in the 1960s to almost 1.0 Pg C yr₋1 during the 2000s due to differences in national reporting errors and differences in energy inventories. Lastly, while land use emissions have remained fairly constant, their errors still remain high and thus their global C uptake uncertainty is not trivial. Currently, the absolute errors in fossil fuel emissions rival the total emissions from land use, highlighting the extent to which fossil fuels dominate the global C budget. Because errors in the atmospheric growth rate have decreased faster than errors in total emissions have increased, a ~20% reduction in the overall uncertainty of net C global uptake has occurred. Given all the major sources of error in the global C budget that we could identify, we are 93% confident that terrestrial C uptake has increased and 97% confident that ocean C uptake has increased over the last 5 decades. Thus, it is clear that arguably one of the most vital ecosystem services currently provided by the biosphere is the continued removal of approximately half

  9. Estimating the Heat and Mass Flux at the ASHES Hydrothermal Vent Field with the Sentry Autonomous Underwater Vehicle

    NASA Astrophysics Data System (ADS)

    Kinsey, J. C.; Crone, T. J.; Mittelstaedt, E. L.; Medagoda, L.; Fourie, D.; Nakamura, K.

    2014-12-01

    Hydrothermal venting influences ocean chemistry, the thermal and chemical structure of the oceanic crust, the style of accretion at mid-ocean ridges, and the evolution of unique and diverse chemosynthetic ecosystems. Surprisingly, only a few studies have attempted to constrain the volume and heat flux of entire hydrothermal vent fields given that axially-hosted hydrothermal systems are estimated to be responsible for ~20-25% of the total heat flux out of the Earth's interior, as well as potentially playing a large role in global and local biogeochemical cycles. However, same-site estimates can vary greatly, such as at the Lucky Strike Field where estimates range from 100 MW to 3800 MW. We report a July 2014 field program with the Sentry AUV that obtains the water velocity and heat measurements necessary to estimate the total heat and mass flux emanating from the ASHES hydrothermal vent field. We equipped Sentry with a Nortek acoustic Doppler velocimeter (ADV) with an inertial measurement unit attached, two acoustic Doppler current profilers (ADCPs), and two SBE3 temperature probes, to measure the temperature and water velocity. This sensing suite provided more accurate measurements than previous AUV based studies. A control volume approach was employed in which Sentry was pre-programmed to survey a 150m by 150m box centered over the vent field flying a "mowing the lawn" pattern at 5m trackline spacing followed by a survey of the perimeter. During a 40 hour survey, the pattern was repeated 9 times allowing us to obtain observations over multiple tidal cycles. Concurrent lowered ADCP (LADCP) measurements were also obtained. Water velocity data obtained with Sentry was corrected for platform motion and then combined with the temperature measurements to estimate heat flux. Analysis of this data is on-going, however these experiments permit us to quantify the heat and mass exiting the control volume, and potentially provide the most accurate and highest resolution heat

  10. Satellite-derived estimations of spatial and seasonal variation in tropospheric carbon dioxide mass over China

    PubMed Central

    Xu, Yuyue; Ke, Changqing; Wang, Juanle; Sun, Jiulin; Liu, Yang; Harris, Warwick; Kou, Cheng

    2013-01-01

    China has frequently been questioned about the data transparency and accuracy of its energy and emission statistics. Satellite-derived remote sensing data potentially provide a useful tool to study the variation in carbon dioxide (CO2) mass over areas of the earth's surface. In this study, Greenhouse gases Observing SATellite (GOSAT) tropospheric CO2 concentration data and NCEP/NCAR reanalysis tropopause data were integrated to obtain estimates of tropospheric CO2 mass variations over the surface of China. These variations were mapped to show seasonal and spatial patterns with reference to China's provincial areas. The estimates of provincial tropospheric CO2 were related to statistical estimates of CO2 emissions for the provinces and considered with reference to provincial populations and gross regional products (GRP). Tropospheric CO2 masses for the Chinese provinces ranged from 53 ± 1 to 14,470 ± 63 million tonnes were greater for western than for eastern provinces and were primarily a function of provincial land area. Adjusted for land area troposphere CO2 mass was higher for eastern and southern provinces than for western and northern provinces. Tropospheric CO2 mass over China varied with season being highest in July and August and lowest in January and February. The average annual emission from provincial energy statistics of CO2 by China was estimated as 10.3% of the average mass of CO2 in the troposphere over China. The relationship between statistical emissions relative to tropospheric CO2 mass was higher than 20% for developed coastal provinces of China, with Shanghai, Tianjin, and Beijing having exceptionally high percentages. The percentages were generally lower than 10% for western inland provinces. Provincial estimates of emissions of CO2 were significantly positively related to provincial populations and gross regional products (GRP) when the values for the provincial municipalities Shanghai, Tianjin, and Beijing were excluded from the linear

  11. Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2012-01-01

    The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

  12. Age and Mass Estimates for 41 Star Clusters in M33

    NASA Astrophysics Data System (ADS)

    Ma, Jun; Zhou, Xu; Chen, Jian-Sheng

    2004-04-01

    In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements with theoretical stellar population synthesis models of Bruzual & Charlot. Also, we calculate the mass of these star clusters using the theoretical M/L_V ratio. The results show that, these star clusters formed continuously in M33 from ˜ 7× 106 -- 1010 years and have masses between ˜ 103 and 2 ×106 M⊙. M33 frames were observed as a part of the BATC Multicolor Survey of the sky in 13 intermediate-band filters from 3800 to 10 000 Å. The relation between age and mass confirms that the sample star cluster masses systematically decrease from the oldest to the youngest.

  13. Estimation of global and regional incidence and prevalence of abdominal aortic aneurysms 1990 to 2010.

    PubMed

    Sampson, Uchechukwu K A; Norman, Paul E; Fowkes, F Gerald R; Aboyans, Victor; Song, Yanna; Harrell, Frank E; Forouzanfar, Mohammad H; Naghavi, Mohsen; Denenberg, Julie O; McDermott, Mary M; Criqui, Michael H; Mensah, George A; Ezzati, Majid; Murray, Christopher

    2014-03-01

    The global burden of abdominal aortic aneurysm (AAA) has not been studied previously. Such information is important given the emergence of cardiovascular diseases in developing countries. We conducted a systematic literature review and estimated the global and regional incidence and prevalence of AAA in 21 world regions by age and sex. The search for prevalence and incidence of AAA using standard clinical and epidemiological terms was conducted using MEDLINE (1950 to 2010), EMBASE (1980 to 2010), AMED (1985 to 2010), CINAHL (1982 to 2010), and LILACS (2008 to 2010). Data abstracted from the systematic review served as priors for Bayesian meta-regression analyses. The analysis drew from 26 high-quality studies to estimate AAA prevalence and incidence. In 1990, the global age-specific prevalence rate per 100,000 ranged from 8.43 (95% CI: 7.03 to 10.14) in the 40 to 44 years age group to 2,422.53 (95% CI: 2,298.63 to 2,562.25) in the 75 to 79 years age group; the corresponding range in 2010 was 7.88 (95% CI: 6.54 to 9.59) to 2,274.82 (95% CI: 2,149.77 to 2,410.17). Prevalence was higher in developed versus developing nations, and the rates within each development stratum decreased between 1990 and 2010. Globally, the age-specific annual incidence rate per 100,000 in 1990 ranged from 0.89 (95% CI: 0.66 to 1.17) in 40 to 44 years age group to 176.08 (95% CI: 162.72 to 190.28) in the 75 to 79 years age group. In 2010, this range was 0.83 (95% CI: 0.61 to 1.11) to 164.57 (95% CI: 152.20 to 178.78). The highest prevalence in 1990 was in Australasia and North America high income regions: 382.65 (95% CI: 356.27 to 410.88) and 300.59 (95% CI: 280.93 to 321.54), respectively. Australasia had the highest prevalence in 2010, although the prevalence decreased to 310.27 (95% CI: 289.01 to 332.94). Regional prevalence increased in Oceania, tropical Latin America, Asia Pacific high income, Southern Sub-Saharan Africa (SSA), Central SSA, South Asia, Western SSA, and Central Asia. AAA

  14. Global Surface Mass Variations From Multiple Geodetic Techniques - Comparison and Assessment

    NASA Astrophysics Data System (ADS)

    Wu, X.; Heflin, M. B.

    2014-12-01

    As a part of the global change process, horizontal water mass transport in the Earth's surface layer leaves several distinct geodetic signatures. These include translational motion between the Earth system's center-of-mass and the center-of-figure of the solid Earth surface, load-induced crustal deformation, time-variable gravity, and ocean bottom pressure (OBP) changes. By measuring or inferring these signatures, the ever-improving dedicated gravity/altimeter mission series and the global geodetic infrastructure of SLR/VLBI/GNSS/DORIS systems have provided an emerging global monitoring capability for the water transport phenomenon. While the different measurement systems can be combined to offer more complete spatio-temporal coverage and better resolution and accuracy, they also contain certain valuable redundancies that can be used to unravel weaknesses or systematic errors. We will present results of several different combination studies using SLR, re-processed GNSS, GRACE, and data-assimilated ocean bottom pressure models from 2002 to 2014. The combination of GNSS deformation/GRACE/OBP results in excellent agreements in geocenter motion and J2 with direct SLR tracking using some network enhancement from VLBI/GNSS/DORIS. During the entire GRACE period, no significant acceleration is detected in geocenter motion along any coordinate axis. GNSS deformation/OBP inversion is also compared in global spatial domain with GRACE indicating significantly improved quality of reprocessed GNSS data. Other combinations have revealed certain discrepancies and disagreements. The results are analyzed and assessed through isolation, perturbation and covariance studies for possible causes and future improvements.

  15. The use of body mass loss to estimate metabolic rate in birds.

    PubMed

    Portugal, Steven J; Guillemette, Magella

    2011-03-01

    During starvation, energy production occurs at the expense of body reserve utilisation which results in body mass loss. Knowing the role of the fuels involved in this body mass loss, along with their energy density, can allow an energy equivalent of mass loss to be calculated. Therefore, it is possible to determine daily energy expenditure (DEE) if two body mass loss measurements at an interval of a few days are obtained. The technique can be cheap, minimally stressful for the animals involved, and the data relatively simple to gather. Here we review the use of body mass loss to estimate DEE in birds through critiquing the strengths and weaknesses of the technique, and detail the methodology and considerations that must be adhered to for accurate measures of DEE to be obtained. Owing to the biology of the species, the use of the technique has been used predominantly in Antarctic seabirds, particularly penguins and albatrosses. We demonstrate how reliable the technique can be in predicting DEE in a non-Antarctic species, common eiders (Somateria mollissima), the female of which undergoes a fasting period during incubation. We conclude that using daily body mass loss to estimate DEE can be a useful and effective approach provided that (1) the substrate being consumed during mass loss is known, (2) the kinetics of body mass loss are understood for the species in question and (3) only species that enter a full phase II of a fast (where substrate catabolism reaches a steady state) and are not feeding for a period of time are appropriate for this method. PMID:21144908

  16. White dwarf mass estimation with a new comprehensive X-ray spectral model of intermediate polars

    NASA Astrophysics Data System (ADS)

    Hayashi, Takayuki; Ishida, Manabu

    A white dwarf (WD) mass is important astrophysical quantity because the WD explodes as a type Ia supernova when its mass reaches the Chandrasekhar mass limit of 1.4 solar mass. Many WD masses in intermediate polars (IPs) were measured with their X-ray spectra emitted from plasma flows channeled by strong magnetic fields of the WDs. For the WD mass estimation, multi-temperature X-ray spectral models have been used which made by summing up X-ray spectra emitted from the top to the bottom of the plasma flow. However, in previous studies, distributions of physical quantities such as temperature and density etc., which are base of the X-ray spectral model, were calculated with assumptions of accretion rate per unit area (call "specific accretion rate") a = 1 g cm(-2) s(-1) and cylindrical geometry for the plasma flows. In fact, a part of the WD masses estimated with the X-ray spectral model is not consistent with that dynamically measured. Therefore, we calculated the physical quantity distributions with the dipolar geometry and the wide range of the specific accretion rate a = 0.0001 - 100 g cm(-2) s(-1) . The calculations showed that the geometrical difference changes the physical quantity distributions and the lower specific accretion rate leads softer X-ray spectrum under a critical specific accretion rate. These results clearly indicate that the previous assumptions are not good approximation for low accretion IPs. We made a new spectral model of the plasma flow with our physical quantity distributions and applied that to Suzaku observations of high and low accretion rate IPs V1223 Sagittarii and EX Hydrae. As a results, our WD masses are almost consistent with the those dynamically measured. We will present the summary of our theoretical calculation and X-ray spectral model, and application to the {¥it Suzaku} observations.

  17. Consistency of Estimated Global Water Cycle Variations Over the Satellite Era

    NASA Technical Reports Server (NTRS)

    Robertson, F. R.; Bosilovich, M. G.; Roberts, J. B.; Reichle, R. H.; Adler, R.; Ricciardulli, L.; Berg, W.; Huffman, G. J.

    2013-01-01

    Motivated by the question of whether recent indications of decadal climate variability and a possible "climate shift" may have affected the global water balance, we examine evaporation minus precipitation (E-P) variability integrated over the global oceans and global land from three points of view-remotely sensed retrievals / objective analyses over the oceans, reanalysis vertically-integrated moisture convergence (MFC) over land, and land surface models forced with observations-based precipitation, radiation and near-surface meteorology. Because monthly variations in area-averaged atmospheric moisture storage are small and the global integral of moisture convergence must approach zero, area-integrated E-P over ocean should essentially equal precipitation minus evapotranspiration (P-ET) over land (after adjusting for ocean and land areas). Our analysis reveals considerable uncertainty in the decadal variations of ocean evaporation when integrated to global scales. This is due to differences among datasets in 10m wind speed and near-surface atmospheric specific humidity (2m qa) used in bulk aerodynamic retrievals. Precipitation variations, all relying substantially on passive microwave retrievals over ocean, still have uncertainties in decadal variability, but not to the degree present with ocean evaporation estimates. Reanalysis MFC and P-ET over land from several observationally forced diagnostic and land surface models agree best on interannual variations. However, upward MFC (i.e. P-ET) reanalysis trends are likely related in part to observing system changes affecting atmospheric assimilation models. While some evidence for a low-frequency E-P maximum near 2000 is found, consistent with a recent apparent pause in sea-surface temperature (SST) rise, uncertainties in the datasets used here remain significant. Prospects for further reducing uncertainties are discussed. The results are interpreted in the context of recent climate variability (Pacific Decadal

  18. Evaluation of global equal-area mass grid solutions from GRACE

    NASA Astrophysics Data System (ADS)

    Save, Himanshu; Bettadpur, Srinivas; Tapley, Byron

    2015-04-01

    The Gravity Recovery and Climate Experiment (GRACE) range-rate data was inverted into global equal-area mass grid solutions at the Center for Space Research (CSR) using Tikhonov Regularization to stabilize the ill-posed inversion problem. These solutions are intended to be used for applications in Hydrology, Oceanography, Cryosphere etc without any need for post-processing. This paper evaluates these solutions with emphasis on spatial and temporal characteristics of the signal content. These solutions will be validated against multiple models and in-situ data sets.

  19. A global empirical model of thermospheric composition based on OGO-6 mass spectrometer measurements

    NASA Technical Reports Server (NTRS)

    Hedin, A. E.; Mayr, H. G.; Reber, C. A.; Carignan, G. R.; Spencer, N. W.

    1972-01-01

    The analysis of composition measurements made with the neutral mass spectrometer aboard the OGO-6 satellite leads to the following conclusions. The measured atomic oxygen densities are generally in good agreement with those deduced from drag. The molecular nitrogen densities in the annual and semiannual variations depart significantly from those predicted by drag models and suggest similar departures for exospheric temperatures. The helium densities generally tend to vary in an inverse manner to the nitrogen densities. These composition changes are consistent with dynamical processes associated with the global circulation in the thermosphere.

  20. Estimation of the auto frequency response function at unexcited points using dummy masses

    NASA Astrophysics Data System (ADS)

    Hosoya, Naoki; Yaginuma, Shinji; Onodera, Hiroshi; Yoshimura, Takuya

    2015-02-01

    If structures with complex shapes have space limitations, vibration tests using an exciter or impact hammer for the excitation are difficult. Although measuring the auto frequency response function at an unexcited point may not be practical via a vibration test, it can be obtained by assuming that the inertia acting on a dummy mass is an external force on the target structure upon exciting a different excitation point. We propose a method to estimate the auto frequency response functions at unexcited points by attaching a small mass (dummy mass), which is comparable to the accelerometer mass. The validity of the proposed method is demonstrated by comparing the auto frequency response functions estimated at unexcited points in a beam structure to those obtained from numerical simulations. We also consider random measurement errors by finite element analysis and vibration tests, but not bias errors. Additionally, the applicability of the proposed method is demonstrated by applying it to estimate the auto frequency response function of the lower arm in a car suspension.

  1. Heavy perfluorocarbons in the global atmosphere: Atmospheric histories and top-down global emission estimates for C4F10, C5F12, C6F14, C7F16 and C8F18

    NASA Astrophysics Data System (ADS)

    Ivy, D. J.; Arnold, T.; Rigby, M. L.; Baasandorj, M.; Muhle, J.; Harth, C.; Salameh, P.; Steele, P.; Leist, M.; Krummel, P. B.; Burkholder, J. B.; Fraser, P.; Weiss, R. F.; Prinn, R. G.

    2011-12-01

    The high molecular weight perfluorocarbons (PFCs) - perfluorobutane (C4F10), perfluoropentane (C5F12), perfluorohexane (C6F14), perfluoroheptane (C7F16) and perfluorooctane (C8F18) - are potent greenhouse gases with global warming potentials of ~ 9000 for a 100 year time horizon [Forster et al., 2007]. Currently, the heavy PFCs are regulated under the Kyoto Protocol of the United Nations Framework Convention on Climate Change (UNFCCC). However, no atmospheric observations or top-down emission estimates for these gases have been published. In this study, atmospheric histories of the heavy PFCs were determined through new measurements of the Cape Grim Air Archive and a collection of Northern Hemispheric archive flasks using the Advanced Global Atmospheric Gases Experiment (AGAGE) cryogenic preconcentration gas chromatography-mass spectrometry system "Medusa" [Miller et al., 2008]. Furthermore, global top-down emissions were estimated from 1973-2010 based on the atmospheric histories using an inverse method and the 3-D chemical transport model, Model of OZone and Related Tracers (MOZARTv4.5) [Emmons et al., 2009]. Comparison of the top-down emission estimates with bottom-up estimates from the Emissions Database for Global Atmospheric Research (EDGARv4.1) shows EDGARv4.1 emission estimates are underestimated by orders of magnitude for C4F10 and C5F12 [European Commission, 2009]. The bottom-up estimates from EDGARv4.1 are comparable to the top-down estimates for C6F14 and C7F16; no bottom-up emission estimates are available for C8F18. Generally, UNFCCC reported inventories by countries that have ratified the Kyoto Protocol are 5 to 10 times lower than the top-down emission estimates for C4F10, C5F12 and C6F14 (C7F16 and C8F18 are not reported to the UNFCCC). The atmospheric histories and top-down emission estimates presented are the most accurate and comprehensive compiled so far for the high molecular weight PFCs. Furthermore, this study illustrates the importance of

  2. Global analysis of the Deinococcus radiodurans proteome by using accurate mass tags

    PubMed Central

    Lipton, Mary S.; Paša-Tolić, Ljiljana; Anderson, Gordon A.; Anderson, David J.; Auberry, Deanna L.; Battista, John R.; Daly, Michael J.; Fredrickson, Jim; Hixson, Kim K.; Kostandarithes, Heather; Masselon, Christophe; Markillie, Lye Meng; Moore, Ronald J.; Romine, Margaret F.; Shen, Yufeng; Stritmatter, Eric; Tolić, Nikola; Udseth, Harold R.; Venkateswaran, Amudhan; Wong, Kwong-Kwok; Zhao, Rui; Smith, Richard D.

    2002-01-01

    Understanding biological systems and the roles of their constituents is facilitated by the ability to make quantitative, sensitive, and comprehensive measurements of how their proteome changes, e.g., in response to environmental perturbations. To this end, we have developed a high-throughput methodology to characterize an organism's dynamic proteome based on the combination of global enzymatic digestion, high-resolution liquid chromatographic separations, and analysis by Fourier transform ion cyclotron resonance mass spectrometry. The peptides produced serve as accurate mass tags for the proteins and have been used to identify with high confidence >61% of the predicted proteome for the ionizing radiation-resistant bacterium Deinococcus radiodurans. This fraction represents the broadest proteome coverage for any organism to date and includes 715 proteins previously annotated as either hypothetical or conserved hypothetical. PMID:12177431

  3. Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking.

    PubMed

    Wang, Mingxun; Carver, Jeremy J; Phelan, Vanessa V; Sanchez, Laura M; Garg, Neha; Peng, Yao; Nguyen, Don Duy; Watrous, Jeramie; Kapono, Clifford A; Luzzatto-Knaan, Tal; Porto, Carla; Bouslimani, Amina; Melnik, Alexey V; Meehan, Michael J; Liu, Wei-Ting; Crüsemann, Max; Boudreau, Paul D; Esquenazi, Eduardo; Sandoval-Calderón, Mario; Kersten, Roland D; Pace, Laura A; Quinn, Robert A; Duncan, Katherine R; Hsu, Cheng-Chih; Floros, Dimitrios J; Gavilan, Ronnie G; Kleigrewe, Karin; Northen, Trent; Dutton, Rachel J; Parrot, Delphine; Carlson, Erin E; Aigle, Bertrand; Michelsen, Charlotte F; Jelsbak, Lars; Sohlenkamp, Christian; Pevzner, Pavel; Edlund, Anna; McLean, Jeffrey; Piel, Jörn; Murphy, Brian T; Gerwick, Lena; Liaw, Chih-Chuang; Yang, Yu-Liang; Humpf, Hans-Ulrich; Maansson, Maria; Keyzers, Robert A; Sims, Amy C; Johnson, Andrew R; Sidebottom, Ashley M; Sedio, Brian E; Klitgaard, Andreas; Larson, Charles B; Boya P, Cristopher A; Torres-Mendoza, Daniel; Gonzalez, David J; Silva, Denise B; Marques, Lucas M; Demarque, Daniel P; Pociute, Egle; O'Neill, Ellis C; Briand, Enora; Helfrich, Eric J N; Granatosky, Eve A; Glukhov, Evgenia; Ryffel, Florian; Houson, Hailey; Mohimani, Hosein; Kharbush, Jenan J; Zeng, Yi; Vorholt, Julia A; Kurita, Kenji L; Charusanti, Pep; McPhail, Kerry L; Nielsen, Kristian Fog; Vuong, Lisa; Elfeki, Maryam; Traxler, Matthew F; Engene, Niclas; Koyama, Nobuhiro; Vining, Oliver B; Baric, Ralph; Silva, Ricardo R; Mascuch, Samantha J; Tomasi, Sophie; Jenkins, Stefan; Macherla, Venkat; Hoffman, Thomas; Agarwal, Vinayak; Williams, Philip G; Dai, Jingqui; Neupane, Ram; Gurr, Joshua; Rodríguez, Andrés M C; Lamsa, Anne; Zhang, Chen; Dorrestein, Kathleen; Duggan, Brendan M; Almaliti, Jehad; Allard, Pierre-Marie; Phapale, Prasad; Nothias, Louis-Felix; Alexandrov, Theodore; Litaudon, Marc; Wolfender, Jean-Luc; Kyle, Jennifer E; Metz, Thomas O; Peryea, Tyler; Nguyen, Dac-Trung; VanLeer, Danielle; Shinn, Paul; Jadhav, Ajit; Müller, Rolf; Waters, Katrina M; Shi, Wenyuan; Liu, Xueting; Zhang, Lixin; Knight, Rob; Jensen, Paul R; Palsson, Bernhard Ø; Pogliano, Kit; Linington, Roger G; Gutiérrez, Marcelino; Lopes, Norberto P; Gerwick, William H; Moore, Bradley S; Dorrestein, Pieter C; Bandeira, Nuno

    2016-08-01

    The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry (MS) techniques are well-suited to high-throughput characterization of NP, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social Molecular Networking (GNPS; http://gnps.ucsd.edu), an open-access knowledge base for community-wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS, crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of 'living data' through continuous reanalysis of deposited data. PMID:27504778

  4. A comparison of global estimates of marine primary production from ocean color

    NASA Astrophysics Data System (ADS)

    Carr, Mary-Elena; Friedrichs, Marjorie A. M.; Schmeltz, Marjorie; Noguchi Aita, Maki; Antoine, David; Arrigo, Kevin R.; Asanuma, Ichio; Aumont, Olivier; Barber, Richard; Behrenfeld, Michael; Bidigare, Robert; Buitenhuis, Erik T.; Campbell, Janet; Ciotti, Aurea; Dierssen, Heidi; Dowell, Mark; Dunne, John; Esaias, Wayne; Gentili, Bernard; Gregg, Watson; Groom, Steve; Hoepffner, Nicolas; Ishizaka, Joji; Kameda, Takahiko; Le Quéré, Corinne; Lohrenz, Steven; Marra, John; Mélin, Frédéric; Moore, Keith; Morel, André; Reddy, Tasha E.; Ryan, John; Scardi, Michele; Smyth, Tim; Turpie, Kevin; Tilstone, Gavin; Waters, Kirk; Yamanaka, Yasuhiro

    2006-03-01

    The third primary production algorithm round robin (PPARR3) compares output from 24 models that estimate depth-integrated primary production from satellite measurements of ocean color, as well as seven general circulation models (GCMs) coupled with ecosystem or biogeochemical models. Here we compare the global primary production fields corresponding to eight months of 1998 and 1999 as estimated from common input fields of photosynthetically-available radiation (PAR), sea-surface temperature (SST), mixed-layer depth, and chlorophyll concentration. We also quantify the sensitivity of the ocean-color-based models to perturbations in their input variables. The pair-wise correlation between ocean-color models was used to cluster them into groups or related output, which reflect the regions and environmental conditions under which they respond differently. The groups do not follow model complexity with regards to wavelength or depth dependence, though they are related to the manner in which temperature is used to parameterize photosynthesis. Global average PP varies by a factor of two between models. The models diverged the most for the Southern Ocean, SST under 10C, and chlorophyll concentration exceeding 1 mg Chl m-3. Based on the conditions under which the model results diverge most, we conclude that current ocean-color-based models are challenged by high-nutrient low-chlorophyll conditions, and extreme temperatures or chlorophyll concentrations. The GCM-based models predict comparable primary production to those based on ocean color: they estimate higher values in the Southern Ocean, at low SST, and in the equatorial band, while they estimate lower values in eutrophic regions (probably because the area of high chlorophyll concentrations is smaller in the GCMs). Further progress in primary production modeling requires improved understanding of the effect of temperature on photosynthesis and better parameterization of the maximum photosynthetic rate.

  5. On Creating Global Gridded Terrestrial Water Budget Estimates from Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Pan, Ming; Wood, Eric F.

    2016-03-01

    The increasing availability and reliability of satellite remote sensing products [e.g., precipitation (P), evapotranspiration (ET), and the total water storage change (TWSC)] make it feasible to estimate the global terrestrial water budget at fine spatial resolution. In this study, we start from a reference water budget dataset that combines all available data sources, including satellite remote sensing, land surface model (LSM) and reanalysis, and investigate the roles of different non-satellite remote sensing products in closing the terrestrial water budget through a sensitivity analysis by removing/replacing one or more categories of products during the budget estimation. We also study the differences made by various satellite products for the same budget variable. We find that the gradual removal of non-satellite data sources will generally worsen the closure errors in the budget estimates, and remote sensing retrievals of P, ET, and TWSC together with runoff (R) from LSM give the worst closure errors. The gauge-corrected satellite precipitation helps to improve the budget closure (4.2-9 % non-closure errors of annual mean precipitation) against using the non-gauge-corrected precipitation (7.6-10.4 % non-closure errors). At last, a data assimilation technique, the constrained Kalman filter, is applied to enforce the water balance, and it is found that the satellite remote sensing products, though with worst closure, yield comparable budget estimates in the constrained system to the reference data. Overall, this study provides a first comparison between the water budget closure using the satellite remote sensing products and a full combination of remote sensing, LSM, and reanalysis products on a quasi-global basis. This study showcases the capability and potential of the satellite remote sensing in closing the terrestrial water budget at fine spatial resolution if properly constrained.

  6. DO QUASAR BROAD-LINE VELOCITY WIDTHS ADD ANY INFORMATION TO VIRIAL BLACK HOLE MASS ESTIMATES?

    SciTech Connect

    Croom, Scott M.

    2011-08-01

    We examine how much information measured broad-line widths add to virial black hole (BH) mass estimates for flux-limited samples of quasars. We do this by comparing the BH mass estimates to those derived by randomly reassigning the quasar broad-line widths to different objects and re-calculating the BH mass. For 9000 BH masses derived from the H{beta} line we find that the distributions of original and randomized BH masses in the M{sub BH}-redshift plane and the M{sub BH}-luminosity plane are formally identical. A two-dimensional Kolmogorov-Smirnov test does not find a difference at >90% confidence. For the Mg II line (32,000 quasars) we do find very significant differences between the randomized and original BH masses, but the amplitude of the difference is still small. The difference for the C IV line (14,000 quasars) is 2{sigma}-3{sigma} and again the amplitude of the difference is small. Subdividing the data into redshift and luminosity bins we find that the median absolute difference in BH mass between the original and randomized data is 0.025, 0.01, and 0.04 dex for H{beta}, Mg II, and C IV, respectively. The maximum absolute difference is always {<=}0.1 dex. We investigate whether our results are sensitive to corrections to Mg II virial masses, such as those suggested by Onken and Kollmeier. These corrections do not influence our results, other than to reduce the significance of the difference between original and randomized BH masses to only 1{sigma}-2{sigma} for Mg II. Moreover, we demonstrate that the correlation between mass residuals and Eddington ratio discussed by Onken and Kollmeier is more directly attributable to the slope of the relation between H{beta} and Mg II line width. The implication is that the measured quasar broad-line velocity widths provide little extra information, after allowing for the mean velocity width. In this case virial estimates are equivalent to M{sub BH}{proportional_to}L{sup {alpha}}, with L/L{sub Edd

  7. Differential interferometry of QSO broad-line regions - I. Improving the reverberation mapping model fits and black hole mass estimates

    NASA Astrophysics Data System (ADS)

    Rakshit, Suvendu; Petrov, Romain G.; Meilland, Anthony; Hönig, Sebastian F.

    2015-03-01

    Reverberation mapping (RM) estimates the size and kinematics of broad-line regions (BLR) in quasars and type I AGNs. It yields size-luminosity relation to make QSOs standard cosmological candles, and mass-luminosity relation to study the evolution of black holes and galaxies. The accuracy of these relations is limited by the unknown geometry of the BLR clouds distribution and velocities. We analyse the independent BLR structure constraints given by super-resolving differential interferometry. We developed a three-dimensional BLR model to compute all differential interferometry and RM signals. We extrapolate realistic noises from our successful observations of the QSO 3C 273 with AMBER on the VLTI. These signals and noises quantify the differential interferometry capacity to discriminate and measure BLR parameters including angular size, thickness, spatial distribution of clouds, local-to-global and radial-to-rotation velocity ratios, and finally central black hole mass and BLR distance. A Markov Chain Monte Carlo model-fit, of data simulated for various VLTI instruments, gives mass accuracies between 0.06 and 0.13 dex, to be compared to 0.44 dex for RM mass-luminosity fits. We evaluate the number of QSOs accessible to observe with current (AMBER), upcoming (GRAVITY) and possible (OASIS with new generation fringe trackers) VLTI instruments. With available technology, the VLTI could resolve more than 60 BLRs, with a luminosity range larger than four decades, sufficient for a good calibration of RM mass-luminosity laws, from an analysis of the variation of BLR parameters with luminosity.

  8. Lidar Approach in Estimating Particulate Mass Emissions from a Poultry Production Facility

    NASA Astrophysics Data System (ADS)

    Lewandowski, P. A.; Eichinger, W. E.; Prueger, J. H.; Hatfield, J.

    2009-12-01

    The current conventional particulate and mass emission measurements from livestock facilities rely primarily on point indoor/outdoor measurements. These measurements combined with assumed outflow rates from a building lead to emission rates and emission factors from the building. This approach, well established in the literature, poses accuracy and representation issues. To overcome the limitations of point measurement emission estimates, a new remote sensing approach is proposed. A scanning elastic lidar was used to estimate the spatially resolved extinction coefficient associated with particulates originating from a poultry production building. Particulate size distribution and wind co-measurements were combined with the lidar extinction coefficient data to estimate particulate mass fluxes and the emission factor from the building. The particulate size distribution was measured continuously since the size distribution changes significantly during the day. Assumptions of constant size distributions may result in errors of a factor of two in derived quantities. The data analysis from the study showed that the average particulate mass emission value from the poultry production building was 0.13±0.04 g/s (460±150 g/h) and the respective emission factor was 3.0±1.0 g/h AU (per animal unit, 500 kg live weight). The lidar estimated values are lower than the values found in the literature from point measurement studies. The study demonstrates a new innovative method in measuring emissions using scanning lidar technique. As presented in the study, the method can successfully address the need for a better tool for emission measurements in agricultural applications. The outlined measurement approach can be also applied, with careful considerations, to any non-point particulate emissions measurement needs in industry or in urban environment. Lidar, particle sizer and wind anemometer data processing flowchart leading to the particulate mass emission estimates

  9. RESEARCH PAPER: Old stellar population synthesis: new age and mass estimates for Mayall II = G1

    NASA Astrophysics Data System (ADS)

    Ma, Jun; de Grijs, Richard; Fan, Zhou; Rey, Soo-Chang; Wu, Zhen-Yu; Zhou, Xu; Wu, Jiang-Hua; Jiang, Zhao-Ji; Chen, Jian-Sheng; Lee, Kyungsook; Sohn, Sangmo Tony

    2009-06-01

    Mayall II = G1 is one of the most luminous globular clusters (GCs) in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHKS 2MASS data, we construct the most extensive spectral energy distribution of G1 to date, spanning the wavelength range from 1538 to 20 000 Å. A quantitative comparison with a variety of simple stellar population (SSP) models yields a mean age which is consistent with G1 being among the oldest building blocks of M31 and having formed within ~1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates (of order 107 Modot) indicate that G1 is one of the most massive GCs in the Local Group. However, we speculate that the cluster's exceptionally high mass suggests that it may not be a genuine GC. Our results also suggest that G1 may contain, on average, (1.65±0.63) × 102 Lodot far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the adopted SSP model. In addition, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs that have similar accuracies as those from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.

  10. Precursor-ion mass re-estimation improves peptide identification on hybrid instruments.

    PubMed

    Luethy, Roland; Kessner, Darren E; Katz, Jonathan E; Maclean, Brendan; Grothe, Robert; Kani, Kian; Faça, Vitor; Pitteri, Sharon; Hanash, Samir; Agus, David B; Mallick, Parag

    2008-09-01

    Mass spectrometry-based proteomics experiments have become an important tool for studying biological systems. Identifying the proteins in complex mixtures by assigning peptide fragmentation spectra to peptide sequences is an important step in the proteomics process. The 1-2 ppm mass-accuracy of hybrid instruments, like the LTQ-FT, has been cited as a key factor in their ability to identify a larger number of peptides with greater confidence than competing instruments. However, in replicate experiments of an 18-protein mixture, we note parent masses deviate 171 ppm, on average, for ion-trap data directed identifications and 8 ppm, on average, for preview Fourier transform (FT) data directed identifications. These deviations are neither caused by poor calibration nor by excessive ion-loading and are most likely due to errors in parent mass estimation. To improve these deviations, we introduce msPrefix, a program to re-estimate a peptide's parent mass from an associated high-accuracy full-scan survey spectrum. In 18-protein mixture experiments, msPrefix parent mass estimates deviate only 1 ppm, on average, from the identified peptides. In a cell lysate experiment searched with a tolerance of 50 ppm, 2295 peptides were confidently identified using native data and 4560 using msPrefixed data. Likewise, in a plasma experiment searched with a tolerance of 50 ppm, 326 peptides were identified using native data and 1216 using msPrefixed data. msPrefix is also able to determine which MS/MS spectra were possibly derived from multiple precursor ions. In complex mixture experiments, we demonstrate that more than 50% of triggered MS/MS may have had multiple precursor ions and note that spectra with multiple candidate ions are less likely to result in an identification using TANDEM. These results demonstrate integration of msPrefix into traditional shotgun proteomics workflows significantly improves identification results. PMID:18707148

  11. COMPARING SINGLE-EPOCH VIRIAL BLACK HOLE MASS ESTIMATORS FOR LUMINOUS QUASARS

    SciTech Connect

    Shen Yue; Liu Xin

    2012-07-10

    Single-epoch virial black hole (BH) mass estimators utilizing broad emission lines have been routinely applied to high-redshift quasars to estimate their BH masses. Depending on the redshift, different line estimators (H{alpha}, H{beta}, Mg II {lambda}2798, C IV {lambda}1549) are often used with optical/near-infrared spectroscopy. Here, we use a homogeneous sample of 60 intermediate-redshift (z {approx} 1.5-2.2) Sloan Digital Sky Survey quasars with optical and near-infrared spectra covering C IV through H{alpha} to investigate the consistency between different single-epoch virial BH mass estimators. We critically compare rest-frame UV line estimators (C IV {lambda}1549, C III] {lambda}1908, and Mg II {lambda}2798) with optical estimators (H{beta} and H{alpha}) in terms of correlations between line widths and between continuum/line luminosities, for the high-luminosity regime (L{sub 5100} > 10{sup 45.4} erg s{sup -1}) probed by our sample. The continuum luminosities of L{sub 1350} and L{sub 3000}, and the broad-line luminosities are well correlated with L{sub 5100}, reflecting the homogeneity of quasar spectra in the rest-frame UV-optical, among which L{sub 1350} and the line luminosities for C IV and C III] have the largest scatter in the correlation with L{sub 5100}. We found that the Mg II FWHM correlates well with the FWHMs of the Balmer lines and that the Mg II line estimator can be calibrated to yield consistent virial mass estimates with those based on the H{beta}/H{alpha} estimators, thus extending earlier results on less luminous objects. The C IV FWHM is poorly correlated with the Balmer line FWHMs, and the scatter between the C IV and H{beta} FWHMs consists of an irreducible part ({approx}0.12 dex), and a part that correlates with the blueshift of the C IV centroid relative to that of H{beta}, similar to earlier studies comparing C IV with Mg II. The C III] FWHM is found to correlate with the C IV FWHM, and hence is also poorly correlated with the H

  12. The global burden of diarrhoeal disease, as estimated from studies published between 1992 and 2000.

    PubMed Central

    Kosek, Margaret; Bern, Caryn; Guerrant, Richard L.

    2003-01-01

    Current estimates of the global burden of disease for diarrhoea are reported and compared with previous estimates made using data collected in 1954-79 and 1980-89. A structured literature review was used to identify studies that characterized morbidity rates by prospective surveillance of stable populations and studies that characterized mortality attributable to diarrhoea through active surveillance. For children under 5 years of age in developing areas and countries, there was a median of 3.2 episodes of diarrhoea per child-year. This indicated little change from previously described incidences. Estimates of mortality revealed that 4.9 children per 1000 per year in these areas and countries died as a result of diarrhoeal illness in the first 5 years of life, a decline from the previous estimates of 13.6 and 5.6 per 1000 per year. The decrease was most pronounced in children aged under 1 year. Despite improving trends in mortality rates, diarrhoea accounted for a median of 21% of all deaths of children aged under 5 years in these areas and countries, being responsible for 2.5 million deaths per year. There has not been a concurrent decrease in morbidity rates attributable to diarrhoea. As population growth is focused in the poorest areas, the total morbidity component of the disease burden is greater than previously. PMID:12764516

  13. Recent top-down estimates of global sources of carbon monoxide

    NASA Astrophysics Data System (ADS)

    Arellano, A. F.; Kasibhatla, P. S.; Giglio, L.

    2003-04-01

    A spatially and temporally robust estimate of the sources of carbon monoxide (CO) is necessary to improve our understanding of tropospheric chemical composition. We present here our synthesis inversion results on CO emission estimates for the year 2000 using NOAA CMDL CO observations and MOPITT derived CO mixing ratios with TRMM VIRS and GBA2000 satellite fire products used as proxies for biomass burning emissions. We compare our results to several regional to global bottom-up and top-down estimates in the past decade. The focus in particular will be on spatially disaggregated anthropogenic sources that are reasonably resolved by present observations. The inverse procedure follows a bayesian approach in estimating a set of scaling factors for these sources that produces the best match of the observations and the modeled CO concentrations, calculated here using GEOS-CHEM chemical transport model. The identifiability of these sources in the inversion is evaluated by detailed a posteriori error analysis including an inspection of the averaging kernels and error patterns.

  14. Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement

    SciTech Connect

    Desantes, J.M.; Galindo, J.; Guardiola, C.; Dolz, V.

    2010-01-15

    Air mass flow determination is needed for the control of current internal combustion engines. Current methods are based on specific sensors (as hot wire anemometers) or indirect estimation through manifold pressure. With the availability of cylinder pressure sensors for engine control, methods based on them can be used for replacing or complementing standard methods. Present paper uses in cylinder pressure increase during the intake stroke for inferring the trapped air mass. The method is validated on two different turbocharged diesel engines and compared with the standard methods. (author)

  15. Accuracy of estimating the masses of Phobos and Deimos from multiple Viking orbiter encounters

    NASA Technical Reports Server (NTRS)

    Tolson, R. H.; Mason, M. L.

    1975-01-01

    The problem was investigated of estimating the masses of Phobos and Deimos from Doppler and onboard optical measurements during the Viking extended mission. A Kalman filter was us