bluuebunny/crossref_metadata_2025_split huggingface dataset:
Examining Coherency Scales, Substructure, and Propagation of Whistler Mode Chorus Elements With Magnetospheric Multiscale (MMS)
Authors: Turner D. L. , Lee J. H. , Claudepierre S. G. , Fennell J. F. , Blake J. B. , Jaynes A. N. , Leonard T. , Wilder F. D. , Ergun R. E. , Baker D. N. , Cohen I. J. , Mauk B. H. , Strangeway R. J. , Hartley D. P. , Kletzing C. A. , Breuillard H. , Le Contel O. , Khotyaintsev Yu. V. , Torbert R. B. , Allen R. C. , Burch J. L. , Santolik O. 
Published: October 2017

AbstractWhistler mode chorus waves are a naturally occurring electromagnetic emission observed in Earth's magnetosphere. Here, for the first time, data from NASA's Magnetospheric Multiscale (MMS) mission were used to analyze chorus waves in detail, including the calculation of chorus wave normal vectors, k. A case study was examined from a period of substorm activity around the time of a conjunction between the MMS constellation and NASA's Van Allen Probes mission on 07 April 2016. Chorus wave activity was simultaneously observed by all six spacecraft over a broad range of L shells (5.5 < L < 8.5), magnetic local time (06:00 < MLT < 09:00), and magnetic latitude (−32° < MLAT < −15°), implying a large chorus active region. Eight chorus elements and their substructure were analyzed in detail with MMS. These chorus elements were all lower band and rising tone emissions, right‐handed and nearly circularly polarized, and propagating away from the magnetic equator when they were observed at MMS (MLAT~−31°). Most of the elements had “hook”‐like signatures on their wave power spectra, characterized by enhanced wave power at flat or falling frequency following the peak, and all the elements exhibited complex and well‐organized substructure observed consistently at all four MMS spacecraft at separations up to 70 km (60 km perpendicular and 38 km parallel to the background magnetic field). The waveforms in field‐aligned coordinates also demonstrated that these waves were all phase coherent, allowing for the direct calculation of k. Error estimates on calculated k revealed that the plane wave approximation was valid for six of the eight elements and most of the subelements. The wave normal vectors were within 20–30° from the direction antiparallel to the background field for all elements and changed from subelement to subelement through at least two of the eight elements. The azimuthal angle of k in the perpendicular plane was oriented earthward and was oblique to that of the Poynting vector, which has implications for the validity of cold plasma theory.
Simultaneous FPI and TMA Measurements of the Lower Thermospheric Wind in the Vicinity of the Poleward Expanding Aurora After Substorm Onset
Authors: Oyama Shin‐ichiro , Kubota Ken , Morinaga Takatoshi , Tsuda Takuo T. , Kurihara Junichi , Larsen Miguel F. , Yamamoto Masayuki , Cai Lei 
Published: October 2017

AbstractLower thermospheric wind fluctuations in the vicinity of an auroral arc immediately before and after a substorm onset were examined by analyzing data from a ground‐based green line Fabry‐Perot interferometer (FPI; optical wavelength of 557.7 nm) at Tromsø, Norway, and in situ measurements from a trimethyl aluminum (TMA) trail released from a sounding rocket launched during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA‐2) campaign on 26 January 2009. Soon after the rocket launch but before disappearance of the TMA trail, a substorm onset occurred. The DELTA‐2 TMA experiment appears to be the first case in which the substorm onset occurred during the TMA wind measurement. It is known that energy dissipation induced by the ionospheric closure current is compacted at the poleward side of the discrete arc in the ionospheric morning cell. Both FPI and TMA measurements were made at the poleward side, but the FPI measured winds nearer to the poleward edge of the arc than the TMA by 110–130 km. The FPI winds at distance of 53–74 km relative to the arc edge showed clear fluctuations immediately after the substorm onset, but there was no obvious similar fluctuation in the TMA‐measured winds. The difference in the response at the two locations suggests that energy dissipation sufficient to be detected as the FPI/TMA wind perturbations was confined to the area from the poleward edge of the arc to a relative distance shorter than 163–203 km but longer than 53–74 km in this event.
Aseismic Motions Drive a Sparse Seismicity During Fluid Injections Into a Fractured Zone in a Carbonate Reservoir
Authors: Duboeuf Laure , De Barros Louis , Cappa Frédéric , Guglielmi Yves , Deschamps Anne , Seguy Simon 
Published: October 2017

AbstractAn increase in fluid pressure in faults can trigger seismicity and large aseismic motions. Understanding how fluid and faults interact is an essential goal for seismic hazard and reservoir monitoring, but this key relation remains unclear. We developed an in situ experiment of fluid injections at a 10 meter scale. Water was injected at high pressure in different geological structures inside a fault damaged zone, in limestone at 280 m depth in the Low Noise Underground Laboratory (France). Induced seismicity, as well as strains, pressure, and flow rate, was continuously monitored during the injections. Although nonreversible deformations related to fracture reactivations were observed for all injections, only a few tests generated seismicity. Events are characterized by a 0.5‐to‐4 kHz content and a small magnitude (approximately −3.5). They are located within 1.5 m accuracy between 1 and 12 m from the injections. Comparing strain measurements and seismicity shows that more than 96% of the deformation is aseismic. The seismic moment is also small compared to the one expected from the injected volume. Moreover, a dual seismic behavior is observed as (1) the spatiotemporal distribution of some cluster of events is clearly independent from the fluid diffusion (2) while a diffusion‐type pattern can be observed for some others clusters. The seismicity might therefore appear as an indirect effect to the fluid pressure, driven by aseismic motion and related stress perturbation transferred through failure.
Estimating Particulate Inorganic Carbon Concentrations of the Global Ocean From Ocean Color Measurements Using a Reflectance Difference Approach
Authors: Mitchell C. , Hu C. , Bowler B. , Drapeau D. , Balch W. M. 
Published: October 2017

AbstractA new algorithm for estimating particulate inorganic carbon (PIC) concentrations from ocean color measurements is presented. PIC plays an important role in the global carbon cycle through the oceanic carbonate pump, therefore accurate estimations of PIC concentrations from satellite remote sensing are crucial for observing changes on a global scale. An extensive global data set was created from field and satellite observations for investigating the relationship between PIC concentrations and differences in the remote sensing reflectance (Rrs) at green, red, and near‐infrared (NIR) wavebands. Three color indices were defined: two as the relative height of Rrs(667) above a baseline running between Rrs(547) and an Rrs in the NIR (either 748 or 869 nm), and one as the difference between Rrs(547) and Rrs(667). All three color indices were found to explain over 90% of the variance in field‐measured PIC. But, due to the lack of availability of Rrs(NIR) in the standard ocean color data products, most of the further analysis presented here was done using the color index determined from only two bands. The new two‐band color index algorithm was found to retrieve PIC concentrations more accurately than the current standard algorithm used in generating global PIC data products. Application of the new algorithm to satellite imagery showed patterns on the global scale as revealed from field measurements. The new algorithm was more resistant to atmospheric correction errors and residual errors in sun glint corrections, as seen by a reduction in the speckling and patchiness in the satellite‐derived PIC images.
Characterization of Particle Backscattering of Global Highly Turbid Waters From VIIRS Ocean Color Observations
Authors: Shi Wei , Wang Menghua 
Published: October 2017

AbstractNormalized water‐leaving radiance spectra nLw(λ) at the near‐infrared (NIR) from five years of observations (2012–2016) with the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar‐orbiting Partnership (SNPP) are used to derive the particle backscattering coefficients bbp(λ) for global highly turbid coastal and inland waters. Based on the fact that the absorption coefficient of sea water aw(λ) is generally much larger than those of the other constituents aiop(λ) at the NIR wavelengths in coastal and inland waters, an NIR‐based bbp(λ) algorithm for turbid coastal and inland waters has been developed and used in this study. This algorithm can be safely used for highly turbid waters with nLw(745) and nLw(862) < ∼6 and ∼4 mW cm−2 μm−1 sr−1, respectively. Seasonal and interannual variations of bbp(λ) in China's east coastal region, the Amazon River Estuary, the La Plata River Estuary, the Meghna River Estuary, the Atchafalaya River Estuary, and Lake Taihu are characterized and quantified. The coefficient bbp(λ) can reach over ∼3–4 m−1 in the Amazon River Estuary and China's east coastal region. The Amazon River Estuary is identified as the most turbid region in the global ocean in terms of bbp(λ) magnitude. bbp(λ) spectra in these five highly turbid regions are also seasonal‐dependent and regional‐dependent. In the highly turbid waters of China's east coastal region and the Amazon River Estuary, bbp(λ) generally increases in wavelength from 410 to 862 nm, while it decreases in the La Plata River Estuary and Atchafalaya River Estuary. This is attributed to the different particle size distributions in these waters. The geophysical implication of the bbp(λ) spectral curvatures for different waters is discussed. To improve global bbp(λ) for both open oceans and coastal turbid waters, a new combined NIR‐based and Quasi‐Analytical Algorithm (QAA)‐based bbp(λ) algorithm is proposed and demonstrated.
Surface Wave Dynamics in Delaware Bay and Its Adjacent Coastal Shelf
Authors: Kukulka Tobias , Jenkins Robert L. , Kirby James T. , Shi Fengyan , Scarborough Robert W. 
Published: October 2017

AbstractThis study presents a broad overview of surface gravity wave dynamics in Delaware Bay and the adjacent continental shelf by employing the wave model Simulating Waves Nearshore one‐way coupled to the ocean model Regional Ocean Modeling System for a period from 2006 to 2012. The distributions of simulated wave statistics agree well with observations obtained from three wave buoys located on the shelf, in the bay near the open ocean, and about 35 km up the bay. A partitioning analysis to separate the two‐dimensional wave height spectrum into wind‐forced and swell parts reveals that waves on the shelf are predominantly remotely generated swell. Bathymetric refraction shelters the bay from energetic open ocean waves, which is supported by an idealized ray tracing analysis. Waves near the bay entrance are also refracted by oblique tidal currents, whose refraction characteristics critically depend on the detailed spatial distributions of the currents. Opposing tidal currents, flowing against the wave propagation direction, focus wave energy outside the bay entrance and in the deeper bay channels, where currents are relatively strong. A spectral partitioning analysis for waves in the bay indicates that less energetic wave fields are likely not directly forced by the wind. More energetic waves, on the other hand, are dominantly driven by winds and the wave response in the bay depends on the fetch‐setting wind direction. Our results for wind‐driven waves in the bay are consistent with previous fetch‐limited observations, but we find a systematic bias between wind and wave directions due to bathymetric refraction.
Large Uncertainties in Urban‐Scale Carbon Emissions
Authors: Gately C. K. , Hutyra L. R. 
Published: October 2017

AbstractAccurate estimates of fossil fuel carbon dioxide (FFCO2) emissions are a critical component of local, regional, and global climate agreements. Current global inventories of FFCO2 emissions do not directly quantify emissions at local scales; instead, spatial proxies like population density, nighttime lights, and power plant databases are used to downscale emissions from national totals. We have developed a high‐resolution (hourly, 1 km2) bottom‐up Anthropogenic Carbon Emissions System (ACES) for FFCO2, based on local activity data for the year 2011 across the northeastern U.S. We compare ACES with three widely used global inventories, finding significant differences at regional (20%) and city scales (50–250%). At a spatial resolution of 0.1°, inventories differ by over 100% for half of the grid cells in the domain, with the largest differences in urban areas and oil and gas production regions. Given recent U.S. federal policy pull backs regarding greenhouse gas emissions reductions, inventories like ACES are crucial for U.S. actions, as the impetus for climate leadership has shifted to city and state governments. The development of a robust carbon monitoring system to track carbon fluxes is critical for emissions benchmarking and verification. We show that existing downscaled inventories are not suitable for urban emissions monitoring, as they do not consider important local activity patterns. The ACES methodology is designed for easy updating, making it suitable for emissions monitoring under most city, regional, and state greenhouse gas mitigation initiatives, in particular, for the small‐ and medium‐sized cities that lack the resources to regularly perform their own bottom‐up emissions inventories.
Nitrogen Losses in Sediments of the East China Sea: Spatiotemporal Variations, Controlling Factors, and Environmental Implications
Authors: Lin Xianbiao , Liu Min , Hou Lijun , Gao Dengzhou , Li Xiaofei , Lu Kaijun , Gao Juan 
Published: October 2017

AbstractGlobal reactive nitrogen (N) has increased dramatically in coastal marine ecosystems over the past decades and caused numerous eco‐environmental problems. Coastal marine sediment plays a critical role in N losses via denitrification and anaerobic ammonium oxidation (anammox) and release of nitrous oxide (N2O). However, both the magnitude and contributions of denitrification, anammox, and N2O production in sediments still remain unclear, causing uncertainty in defining the N budget for coastal marine ecosystems. Here potential rates of N losses, and their contributions and controlling factors, were investigated in surface sediments during six cruises from 429 sites of the East China Sea. The potential rates of denitrification, anammox, and N2O production varied both spatially and seasonally, but the contribution of anammmox to total N2 production (%anammox) and N2O:N2 ratio only varied spatially. Both organic carbon and nitrate (NO3−) were important factors controlling N losses, N2O:N2 ratio, and %anammox. Our results also showed that marine organic carbon induced by eutrophication plays an important role in stimulating reactive N removal and increasing N2O production in warm seasons. The sediment N loss caused by denitrification, anammox, and N2O production in the study area were estimated at 2.2 × 106 t N yr−1, 4.6 × 105 t N yr−1, and 8 × 103 t N yr−1, respectively. Although sediments remove large quantities of reactive N, they act as an important source of N2O in this region influenced by NO3−‐laden rivers.
Improved Winter European Atmospheric Blocking Frequencies in High‐Resolution Global Climate Simulations
Authors: Davini P. , Corti S. , D'Andrea F. , Rivière G. , von Hardenberg J. 
Published: October 2017

AbstractThe numerical simulation of atmospheric blocking, in particular over the Euro‐Atlantic region, still represents a main concern for the climate modeling community. We discuss the Northern Hemisphere winter atmospheric blocking representation in a set of 30 year atmosphere‐only simulations using the EC‐Earth Earth System Model with several ensemble members at five different horizontal resolutions (from 125 to 16 km). Results show that the negative bias in blocking frequency over Europe becomes negligible at resolutions of about 40 and 25 km. A combined effect by the more resolved orography and by a change in tropical precipitation is identified as the source of an upper tropospheric planetary wave. At the same time, a weakening of the meridional temperature gradient reduces the upper level baroclinicity and the zonal mean winds. Following these changes, in the high‐resolution configurations the Atlantic eddy‐driven jet stream is weakened favoring the breaking of synoptic Rossby waves over the Atlantic ridge and thus increasing the simulated European blocking frequency. However, at high‐resolution the Atlantic jet stream is too weak and the blocking duration is still underestimated. This suggests that the optimal blocking frequencies are achieved through compensation of errors between eddies found at upper levels (too strong) and eddies at lower levels (too weak). This also implies that eddies are not necessarily better represented at higher resolutions.
Multiple Household Water Sources and Their Use in Remote Communities With Evidence From Pacific Island Countries
Authors: Elliott Mark , MacDonald Morgan C. , Chan Terence , Kearton Annika , Shields Katherine F. , Bartram Jamie K. , Hadwen Wade L. 
Published: October 2017

AbstractGlobal water research and monitoring typically focus on the household's “main source of drinking‐water.” Use of multiple water sources to meet daily household needs has been noted in many developing countries but rarely quantified or reported in detail. We gathered self‐reported data using a cross‐sectional survey of 405 households in eight communities of the Republic of the Marshall Islands (RMI) and five Solomon Islands (SI) communities. Over 90% of households used multiple sources, with differences in sources and uses between wet and dry seasons. Most RMI households had large rainwater tanks and rationed stored rainwater for drinking throughout the dry season, whereas most SI households collected rainwater in small pots, precluding storage across seasons. Use of a source for cooking was strongly positively correlated with use for drinking, whereas use for cooking was negatively correlated or uncorrelated with nonconsumptive uses (e.g., bathing). Dry season water uses implied greater risk of water‐borne disease, with fewer (frequently zero) handwashing sources reported and more unimproved sources consumed. Use of multiple sources is fundamental to household water management and feasible to monitor using electronic survey tools. We contend that recognizing multiple water sources can greatly improve understanding of household‐level and community‐level climate change resilience, that use of multiple sources confounds health impact studies of water interventions, and that incorporating multiple sources into water supply interventions can yield heretofore‐unrealized benefits. We propose that failure to consider multiple sources undermines the design and effectiveness of global water monitoring, data interpretation, implementation, policy, and research.
Functional Topology of Evolving Urban Drainage Networks
Authors: Yang Soohyun , Paik Kyungrock , McGrath Gavan S. , Urich Christian , Krueger Elisabeth , Kumar Praveen , Rao P. Suresh C. 
Published: October 2017

AbstractWe investigated the scaling and topology of engineered urban drainage networks (UDNs) in two cities, and further examined UDN evolution over decades. UDN scaling was analyzed using two power law scaling characteristics widely employed for river networks: (1) Hack's law of length (L)‐area (A) [
] and (2) exceedance probability distribution of upstream contributing area (δ) [
]. For the smallest UDNs (<2 km2), length‐area scales linearly (h ∼ 1), but power law scaling (h ∼ 0.6) emerges as the UDNs grow. While
plots for river networks are abruptly truncated, those for UDNs display exponential tempering [
]. The tempering parameter c decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power law exponent ɛ for large UDNs tends to be greater than the range reported for river networks. Differences in generative processes and engineering design constraints contribute to observed differences in the evolution of UDNs and river networks, including subnet heterogeneity and nonrandom branching.
Nine Hundred Years of Weekly Streamflows: Stochastic Downscaling of Ensemble Tree‐Ring Reconstructions
Authors: Sauchyn David , Ilich Nesa 
Published: October 2017

AbstractWe combined the methods and advantages of stochastic hydrology and paleohydrology to estimate 900 years of weekly flows for the North and South Saskatchewan Rivers at Edmonton and Medicine Hat, Alberta, respectively. Regression models of water‐year streamflow were constructed using historical naturalized flow data and a pool of 196 tree‐ring (earlywood, latewood, and annual) ring‐width chronologies from 76 sites. The tree‐ring models accounted for up to 80% of the interannual variability in historical naturalized flows. We developed a new algorithm for generating stochastic time series of weekly flows constrained by the statistical properties of both the historical record and proxy streamflow data, and by the necessary condition that weekly flows correlate between the end of a year and the start of the next. A second innovation, enabled by the density of our tree‐ring network, is to derive the paleohydrology from an ensemble of 100 statistically significant reconstructions at each gauge. Using paleoclimatic data to generate long series of weekly flow estimates augments the short historical record with an expanded range of hydrologic variability, including sequences of wet and dry years of greater length and severity. This unique hydrometric time series will enable evaluation of the reliability of current water supply and management systems given the range of hydroclimatic variability and extremes contained in the stochastic paleohydrology. It also could inform evaluation of the uncertainty in climate model projections, given that internal hydroclimatic variability is the dominant source of uncertainty.
Adsorbed Eutectic GaIn Structures on a Neoprene Foam for Stretchable MRI Coils
Authors: Varga Matija , Mehmann Andreas , Marjanovic Josip , Reber Jonas , Vogt Christian , Pruessmann Klaas Paul , Tröster Gerhard 
Published: October 2017

AbstractStretchable conductors based on eutectic gallium–indium (eGaIn) alloy are patterned on a polychloroprene substrate (neoprene foam) using stencil printing. By tuning the amount of eGaIn on the neoprene substrate, different strain‐sensitivity of electrical resistance is achieved. Conductors with a layer of eGaIn, which adsorbs to the walls of 60–100 µm wide neoprene cells, change their electrical resistance for 5% at 100% strain. When the amount of eGaIn is increased, the cells are filled with eGaIn and the strain‐sensitivity of the electrical resistance rises to 300% at 100% strain. The developed conductors are patterned as stretchable on‐body coils for receiving magnetic signals in a clinical magnetic resonance imaging setup. First images with a stretchable coil are acquired on an orange and compared to the images that are recorded using a rigid copper coil of the same size.