bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observation and interpretation of energetic ion conics in Jupiter's polar magnetosphere
Authors: Clark G. , Mauk B. H. , Paranicas C. , Haggerty D. , Kollmann P. , Rymer A. , Brown L. , Jaskulek S. , Schlemm C. , Kim C. , Peachey J. , LaVallee D. , Allegrini F. , Bagenal F. , Bolton S. , Connerney J. , Ebert R. W. , Hospodarsky G. , Levin S. , Kurth W. S. , McComas D. J. , Mitchell D. G. , Ranquist D. , Valek P. 
Published: May 2017

AbstractNASA's Juno spacecraft successfully completed its first science polar pass over Jupiter's northern and southern aurora, with all the instruments powered, on 27 August 2016. Observations of conical energetic proton distributions at low altitudes (<6 RJ) over the northern polar region are interpreted as resulting from transversely (to the local magnetic field lines) accelerated H+ at a position planetward of the point of observation. The proton conics were observed within a broad region of upward beaming electrons and were accompanied by broadband low‐frequency wave emissions as well as low‐altitude trapped magnetospheric protons and heavy ions. The characteristic energies associated with these accelerated ion conics are ~100 times more energetic than similar distributions observed in the Earth's auroral region and similar in energy to those found at Saturn. In addition, the ion conics also exhibited pitch angle dispersion with time that is interpreted as a consequence of the structure of the source location. Mapping these distributions along magnetic field lines connected from the spacecraft to the ionosphere suggests that the source region exists at altitudes between ~3 and 5 RJ. These new and exciting observations of accelerated ions over the polar region of Jupiter open up new areas for comparative planetary auroral physics.
The first close‐up images of Jupiter's polar regions: Results from the Juno mission JunoCam instrument
Authors: Orton Glenn S. , Hansen Candice , Caplinger Michael , Ravine Michael , Atreya Sushil , Ingersoll Andrew P. , Jensen Elsa , Momary Thomas , Lipkaman Leslie , Krysak Daniel , Zimdar Robert , Bolton Scott 
Published: May 2017

AbstractDuring Juno's first perijove encounter, the JunoCam instrument acquired the first images of Jupiter's polar regions at 50–70 km spatial scale at low emission angles. Poleward of 64–68° planetocentric latitude, where Jupiter's east‐west banded structure breaks down, several types of discrete features appear on a darker background. Cyclonic oval features are clustered near both poles. Other oval‐shaped features are also present, ranging in size from 2000 km down to JunoCam's resolution limits. The largest and brightest features often have chaotic shapes. Two narrow linear features in the north, associated with an overlying haze feature, traverse tens of degrees of longitude. JunoCam also detected an optically thin cloud or haze layer past the northern nightside terminator estimated to be 58 ± 21 km (approximately three scale heights) above the main cloud deck. JunoCam will acquire polar images on every perijove, allowing us to track the state and evolution of longer‐lived features.
Multivariate Copula Analysis Toolbox (MvCAT): Describing dependence and underlying uncertainty using a Bayesian framework
Authors: Sadegh Mojtaba , Ragno Elisa , AghaKouchak Amir 
Published: May 2017

AbstractWe present a newly developed Multivariate Copula Analysis Toolbox (MvCAT) which includes a wide range of copula families with different levels of complexity. MvCAT employs a Bayesian framework with a residual‐based Gaussian likelihood function for inferring copula parameters and estimating the underlying uncertainties. The contribution of this paper is threefold: (a) providing a Bayesian framework to approximate the predictive uncertainties of fitted copulas, (b) introducing a hybrid‐evolution Markov Chain Monte Carlo (MCMC) approach designed for numerical estimation of the posterior distribution of copula parameters, and (c) enabling the community to explore a wide range of copulas and evaluate them relative to the fitting uncertainties. We show that the commonly used local optimization methods for copula parameter estimation often get trapped in local minima. The proposed method, however, addresses this limitation and improves describing the dependence structure. MvCAT also enables evaluation of uncertainties relative to the length of record, which is fundamental to a wide range of applications such as multivariate frequency analysis.
Radiation near Jupiter detected by Juno/JEDI during PJ1 and PJ3
Authors: Paranicas C. , Mauk B. H. , Haggerty D. K. , Clark G. , Kollmann P. , Rymer A. M. , Szalay J. R. , Ranquist D. , Bagenal F. , Levin S. M. , Connerney J. E. P. , Bolton S. J. 
Published: May 2017

AbstractAfter its capture into Jupiter orbit early in the summer of 2016, the Juno spacecraft made three close flybys of the planet to date. The Jupiter Energetic Particle Detector Instrument (JEDI) made continuous measurements during perijoves in late August and early December. Here we describe the radiation (approximately hundreds of keV to more than 10 MeV charged particles) that was measured close to Jupiter. The purpose of this paper is to present some of the first direct energetic charged particle measurements ever obtained at high magnetic latitude very close to Jupiter and to interpret these data using techniques that rely on the instrument design. We generate an electron energy spectrum in an intense radiation region where the JEDI foreground is only about 40% of the rate due to >15 MeV electrons.
Preliminary JIRAM results from Juno polar observations: 2. Analysis of the Jupiter southern H3+ emissions and comparison with the north aurora
Authors: Adriani A. , Mura A. , Moriconi M. L. , Dinelli B. M. , Fabiano F. , Altieri F. , Sindoni G. , Bolton S. J. , Connerney J. E. P. , Atreya S. K. , Bagenal F. , Gérard J.‐C. M. C. , Filacchione G. , Tosi F. , Migliorini A. , Grassi D. , Piccioni G. , Noschese R. , Cicchetti A. , Gladstone G. R. , Hansen C. , Kurth W. S. , Levin S. M. , Mauk B. H. , McComas D. J. , Olivieri A. , Turrini D. , Stefani S. , Amoroso M. 
Published: May 2017

AbstractThe Jupiter InfraRed Auroral Mapper (JIRAM) aboard Juno observed the Jovian South Pole aurora during the first orbit of the mission. H3+ (trihydrogen cation) and CH4 (methane) emissions have been identified and measured. The observations have been carried out in nadir and slant viewing both by a L‐filtered imager and a 2–5 μm spectrometer. Results from the spectral analysis of the all observations taken over the South Pole by the instrument are reported. The coverage of the southern aurora during these measurements has been partial, but sufficient to determine different regions of temperature and abundance of the H3+ ion from its emission lines in the 3–4 μm wavelength range. Finally, the results from the southern aurora are also compared with those from the northern ones from the data taken during the same perijove pass and reported by Dinelli et al. (2017).
Infrared observations of Jovian aurora from Juno's first orbits: Main oval and satellite footprints
Authors: Mura A. , Adriani A. , Altieri F. , Connerney J. E. P. , Bolton S. J. , Moriconi M. L. , Gérard J.‐C. , Kurth W. S. , Dinelli B. M. , Fabiano F. , Tosi F. , Atreya S. K. , Bagenal F. , Gladstone G. R. , Hansen C. , Levin S. M. , Mauk B. H. , McComas D. J. , Sindoni G. , Filacchione G. , Migliorini A. , Grassi D. , Piccioni G. , Noschese R. , Cicchetti A. , Turrini D. , Stefani S. , Amoroso M. , Olivieri A. 
Published: May 2017

AbstractThe Jovian Infrared Auroral Mapper (JIRAM) is an imager/spectrometer on board NASA/Juno mission for the study of the Jovian aurorae. The first results of JIRAM's imager channel observations of the H3+ infrared emission, collected around the first Juno perijove, provide excellent spatial and temporal distribution of the Jovian aurorae, and show the morphology of the main ovals, the polar regions, and the footprints of Io, Europa and Ganymede. The extended Io “tail” persists for ~3 h after the passage of the satellite flux tube. Multi‐arc structures of varied spatial extent appear in both main auroral ovals. Inside the main ovals, intense, localized emissions are observed. In the southern aurora, an evident circular region of strong depletion of H3+ emissions is partially surrounded by an intense emission arc. The southern aurora is brighter than the north one in these observations. Similar, probably conjugate emission patterns are distinguishable in both polar regions.
Electron butterfly distributions at particular magnetic latitudes observed during Juno's perijove pass
Authors: Ma Q. , Thorne R. M. , Li W. , Zhang X.‐J. , Mauk B. H. , Paranicas C. , Haggerty D. K. , Kurth W. S. , Connerney J. E. P. , Bagenal F. , Bolton S. J. 
Published: May 2017

AbstractWe report observations of energetic electron butterfly distributions measured in a narrow range of Jupiter's magnetic latitudes by Juno during perijove 1. The electron butterfly distributions are characterized as clear electron flux peaks at 30–80° pitch angles, compared with the 90°‐peaked pitch angle distributions of the trapped electrons. Jupiter Energetic Particle Detector Instrument measurements during the close approach to Jupiter indicate a specific electron population with butterfly distributions formed between the main auroral oval and the radiation belt. The off‐90° flux peak is most clearly observed at tens of keV energies and gradually merges toward 90° pitch angle at higher energies. By projecting the observed electron pitch angle distributions along the magnetic field line, we found that the electron butterfly distributions are observed close to their source region. The particular electron distribution is possibly formed by parallel acceleration of electrons through Landau resonance with electrostatic waves.
Magnetosphere‐ionosphere coupling at Jupiter: Expectations for Juno Perijove 1 from a steady state axisymmetric physical model
Authors: Cowley S. W. H. , Provan G. , Bunce E. J. , Nichols J. D. 
Published: May 2017

AbstractWe evaluate the expected effects of magnetosphere‐ionosphere coupling at Jupiter along the Juno Perijove 1 (PJ1) trajectory using an axisymmetric physical model. As found at Saturn, the model predicts distributed downward field‐aligned currents over polar regions mapping to the tail and outer magnetosphere, closed principally through a ring of upward current mapping to the middle magnetosphere, which requires downward acceleration of magnetospheric electrons generating Jupiter's main auroral emission. Auroral location, width, intensity, electron energy, and current density are in accord with values derived from previous ultraviolet imaging, such that the model forms an appropriate baseline for comparison with Juno data. We evaluate the azimuthal field perturbations during six anticipated near‐planet encounters with middle magnetosphere field lines at radial distances between ~1.6 and ~16 Jovian radii, discuss the expected form of the accelerated electron distributions, and comment briefly on model expectations in relation to first results derived from Juno PJ1 data.
Jupiter gravity field estimated from the first two Juno orbits
Authors: Folkner W. M. , Iess L. , Anderson J. D. , Asmar S. W. , Buccino D. R. , Durante D. , Feldman M. , Gomez Casajus L. , Gregnanin M. , Milani A. , Parisi M. , Park R. S. , Serra D. , Tommei G. , Tortora P. , Zannoni M. , Bolton S. J. , Connerney J. E. P. , Levin S. M. 
Published: May 2017

AbstractThe combination of the Doppler data from the first two Juno science orbits provides an improved estimate of the gravity field of Jupiter, crucial for interior modeling of giant planets. The low‐degree spherical harmonic coefficients, especially J4 and J6, are determined with accuracies better than previously published by a factor of 5 or more. In addition, the independent estimates of the Jovian gravity field, obtained by the orbits separately, agree within uncertainties, pointing to a good stability of the solution. The degree 2 sectoral and tesseral coefficients, C2,1, S2,1, C2,2, and S2,2, were determined to be statistically zero as expected for a fluid planet in equilibrium.
Statistical study of latitudinal beaming of Jupiter's decametric radio emissions using Juno
Authors: Imai Masafumi , Kurth William S. , Hospodarsky George B. , Bolton Scott J. , Connerney John E. P. , Levin Steven M. 
Published: May 2017

AbstractSynoptic decametric (DAM) radio observations at Jupiter were made in a broad Jovicentric latitudinal range of −21° to +15° by the Juno polar orbiting spacecraft from 21 June to 10 December 2016. We investigated the occurrence probability of non‐Io‐related DAM. At 19.5 MHz, as Juno's latitude varies from +15° to −21°, a peak of non‐Io‐B occurrence probability at 175° System III central meridian longitude (CML) gradually shifts in longitude to 140° CML. Also, another peak occurs at 110° CML between −15° and −9°, merging into the bottom edge of the former peak. This J‐shaped feature is similarly seen at 16.5 MHz. Using the Jovian magnetic field models, the fixed hollow cone model can reasonably account for the J‐shaped structure for radio sources traced along active magnetic flux tubes onto Jupiter's surface projected at about 135°–149° System III longitude. Moreover, these non‐Io‐B spectral profiles extend from 13.5 to 23.5 MHz.
An analytical model of maximum potential intensity for tropical cyclones incorporating the effect of ocean mixing
Authors: Miyamoto Yoshiaki , Bryan George H. , Rotunno Richard 
Published: May 2017

AbstractAn analytical model of maximum potential intensity (PI) for tropical cyclones (TCs) incorporating wind‐induced ocean cooling is developed on the basis of Emanuel's PI theory. The model consists of a one‐dimensional ocean and an axisymmetric TC vortex that is translating at a constant speed. The model advances upon previous approaches by accounting for TC size and shape. The PI is determined at the radius of maximum winds by radially integrating the effect of ocean mixing using a specified wind profile. The resulting analytic ocean cooling agrees well with numerical solutions, and the new PI model better captures maximum intensities of observed TCs compared with Emanuel's original PI. It is also shown that the degree of cooling (i.e., ocean's feedback to atmosphere) can be quantified by a dimensionless parameter, representing the ratio of atmospheric forcing to ocean stability.
A Bayesian hierarchical model for climate change detection and attribution
Authors: Katzfuss Matthias , Hammerling Dorit , Smith Richard L. 
Published: May 2017

AbstractRegression‐based detection and attribution methods continue to take a central role in the study of climate change and its causes. Here we propose a novel Bayesian hierarchical approach to this problem, which allows us to address several open methodological questions. Specifically, we take into account the uncertainties in the true temperature change due to imperfect measurements, the uncertainty in the true climate signal under different forcing scenarios due to the availability of only a small number of climate model simulations, and the uncertainty associated with estimating the climate variability covariance matrix, including the truncation of the number of empirical orthogonal functions (EOFs) in this covariance matrix. We apply Bayesian model averaging to assign optimal probabilistic weights to different possible truncations and incorporate all uncertainties into the inference on the regression coefficients. We provide an efficient implementation of our method in a software package and illustrate its use with a realistic application.
Variability in seasonal forecast skill of Northern Hemisphere winters over the twentieth century
Authors: O'Reilly Christopher H. , Heatley James , MacLeod Dave , Weisheimer Antje , Palmer Tim N. , Schaller Nathalie , Woollings Tim 
Published: May 2017

AbstractSeasonal hindcast experiments, using prescribed sea surface temperatures (SSTs), are analyzed for Northern Hemisphere winters from 1900 to 2010. Ensemble mean Pacific/North American index (PNA) skill varies dramatically, dropping toward zero during the mid‐twentieth century, with similar variability in North Atlantic Oscillation (NAO) hindcast skill. The PNA skill closely follows the correlation between the observed PNA index and tropical Pacific SST anomalies. During the mid‐century period the PNA and NAO hindcast errors are closely related. The drop in PNA predictability is due to mid‐century negative PNA events, which were not forced in a predictable manner by tropical Pacific SST anomalies. Overall, negative PNA events are less predictable and seem likely to arise more from internal atmospheric variability than positive PNA events. Our results suggest that seasonal forecasting systems assessed over the recent 30 year period may be less skillful in periods, such as the mid‐twentieth century, with relatively weak forcing from tropical Pacific SST anomalies.
The coastal mean dynamic topography in Norway observed by CryoSat‐2 and GOCE
Authors: Idžanović Martina , Ophaug Vegard , Andersen Ole Baltazar 
Published: May 2017

AbstractNew‐generation synthetic aperture radar altimetry, as implemented on CryoSat‐2, observes sea surface heights in coastal areas that were previously not monitored by conventional altimetry. Therefore, CryoSat‐2 is expected to improve the coastal mean dynamic topography (MDT). However, the MDT remains highly reliant on the geoid. Using new regional geoid models as well as CryoSat‐2 data, we determine three geodetic coastal MDT models in Norway and validate them against independent tide‐gauge observations and the operational coastal ocean model NorKyst800. The CryoSat‐2 MDTs agree on the ∼3–5 cm level with both tide‐gauge geodetic and ocean MDTs along the Norwegian coast. In addition, we compute geostrophic surface currents to help identifying errors in the geoid models. We find that even though the regional geoid models are all based on the latest satellite gravity data as provided by GOCE, the resulting circulation patterns differ. We demonstrate that some of these differences are due to erroneous or lack of marine gravity data. This suggests that there is significant MDT signal at spatial scales beyond GOCE, and that the geodetic approach to MDT determination benefits from the additional terrestrial gravity information provided by a regional geoid model. We also find that the border of the geographical mode mask of CryoSat‐2 coincides with the Norwegian Coastal Current, making it challenging to distinguish between artifacts in the CryoSat‐2 observations during mode switch and ocean signal.
Introduction and evaluation of a Weibull hydraulic conductivity‐pressure head relationship for unsaturated soils
Authors: Assouline Shmuel , Selker John 
Published: May 2017

AbstractAnalytical and numerical solutions for flow through partially saturated soils typically require functional relationships between water content, pressure, and hydraulic conductivity. Here we propose a Weibull‐type function to describe the hydraulic conductivity‐pressure head function. We show that this is a more flexible function that has the ability to address air entry pressure, while retaining the ease of integration and differentiation that facilitates many important computations which have to this point favored the Gardner exponential function (which is a special case of the proposed function). The ability to fit measured values is shown to be better than commonly employed functions of similar simplicity. Strong relationships were found between the parameters of the proposed function and the corresponding soil water retention curve, thus providing predictive capability. A simple relationship was also found between the parameters of the function and the wetting front pressure, ψf. Applying the proposed function to estimate ψf improves the accuracy of predictions for infiltration using the Green and Ampt model.
Graphdiyne Filter for Decontaminating Lead‐Ion‐Polluted Water
Authors: Liu Rong , Zhou Jingyuan , Gao Xin , Li Jiaqiang , Xie Ziqian , Li Zhenzhu , Zhang Shuqing , Tong Lianming , Zhang Jin , Liu Zhongfan 
Published: May 2017

AbstractThe decontamination of water polluted with heavy metal ions is of worldwide concern. Among various treatment approaches to remove metal ions from water, adsorption is regarded as an efficient method, and a variety of materials have been applied as adsorbents for the removal of metal ions from polluted water. Recently, carbon nanomaterials have been examined as alternative adsorbents due to their high specific surface areas, high removal efficiency, and strong interactions with metal ions. Graphdiyne, a new kind of carbon allotrope composed of sp‐ and sp2‐hybridized carbon atoms, has attracted great interest due to its impressive properties. Graphdiyne is considered to be a promising candidate for the adsorption of heavy metal ions as the acetylenic links in graphdiyne strongly interact with metal ions. Herein, graphdiyne is used as an adsorbent to remove lead ions from water. The interaction between lead ions and graphdiyne is explored by X‐ray photoelectron spectroscopy and Raman spectroscopy. The maximum adsorption capacity calculated by the Langmuir isotherm model is 470.5 mg g−1. Graphdiyne is also synthesized on copper foam and used as a filter to eliminate lead ions from water. The filter shows high performance with a removal efficiency of 99.6% and can be recovered through treatment with acidic solution.
Temporal trends in craniometric estimates of admixture for a modern American sample
Authors: Algee‐Hewitt Bridget F. B. 
Published: May 2017

AbstractObjectivesTemporal trends in craniometric estimates of admixture are investigated for three U.S. populations in the FDB. Patterns of association between birth years and posterior probabilities of cluster membership are identified to assess how these proportions of admixture have changed over recent time. Demographic and genetic data correlates, patterns of morphological expression, and shifts in source populations are evaluated.Materials and MethodsEstimates of three‐way admixture were obtained for 1,521 individuals of documented population, sex, and birth years that span the 20th century. Correlations were calculated between birth years and admixture proportions for members of each FDB population. Population and sex‐specific admixture variation was further assessed by ANOVA and regression. Correlation analysis was used to identify, per population, which of the cranial measurements change in dimension under increased or decreased admixture.ResultsAdmixture proportions differ significantly by population and change over time. No sex differences are detected. Analysis of the relationship between admixture proportions and ILDs finds that admixture drives morphological change in areas of the cranium known to vary among populations. Results agree with prior work on secular change.DiscussionFindings reveal a progressive increase in White‐European population admixture for the self‐identified Black individuals, a recent demographic shift toward the increased representation of Hispanic individuals carrying greater Native American ancestry, and reduction in admixture for White individuals that suggest a loss of diversity over time. Changes in admixture produce tractable differences in morphological expression. Both sexes exhibit similar admixture proportions and self‐identification patterns. Observed diachronic trends are corroborated by information on recent U.S. demographic change.