bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sea Surface Salinity Signature of the Tropical Atlantic Interannual Climatic Modes
Authors: Awo F. M. , Alory G. , Da‐Allada C. Y. , Delcroix T. , Jouanno J. , Kestenare E. , Baloïtcha E. 
Published: September 2018

AbstractThe characteristic sea surface salinity (SSS) patterns associated with the tropical Atlantic meridional and equatorial interannual modes are extracted from in situ observations, by a statistical analysis performed on the 1980–2012 period. These SSS signatures of the interannual climatic modes are reproduced in a regional numerical simulation. For each mode, oceanic and/or atmospheric processes driving the SSS signature are identified through a mixed‐layer salt budget in the validated model. During a positive meridional mode in spring, a northward shift of the Intertropical Convergence Zone and related precipitation maximum creates a south‐north dipole of positive‐negative SSS anomalies around the equator. Western boundary currents strengthen and advect relatively fresh equatorial waters, which creates negative SSS anomalies in the north and south west tropical Atlantic. Meridional and vertical advection create positive SSS anomalies off the Congo River. During a positive equatorial mode in summer, a southward shift of the Intertropical Convergence Zone‐related rainfall maximum creates a south‐north dipole of negative‐positive SSS anomalies between the equator and 10°N. Meridional advection also contributes to the positive SSS anomalies between 5°N and 10°N. Vertical advection and diffusion at the mixed‐layer base create positive SSS anomalies between 5°S and the equator. Horizontal advection creates large SSS anomalies in the North Brazil Current retroflection region, negative along the coast and positive further offshore. The SSS signatures of the meridional and equatorial modes described above are well captured by the Soil Moisture–Ocean Salinity satellite during the 2010 and 2012 events.
Impact of Seabed Resuspension on Oxygen and Nitrogen Dynamics in the Northern Gulf of Mexico: A Numerical Modeling Study
Authors: Moriarty Julia M. , Harris Courtney K. , Friedrichs Marjorie A. M. , Fennel Katja , Xu Kehui 
Published: September 2018

AbstractResuspension affects water quality in coastal environments by entraining seabed organic matter into the water column, which can increase remineralization, alter seabed fluxes, decrease water clarity, and affect oxygen and nutrient dynamics. Nearly all numerical models of water column biogeochemistry, however, simplify seabed and bottom boundary layer processes and neglect resuspension. Here we implemented HydroBioSed, a coupled hydrodynamic‐sediment transport‐biogeochemical model to examine the role of resuspension in regulating oxygen and nitrogen dynamics on timescales of a day to a month. The model was implemented for the northern Gulf of Mexico, where the extent of summertime hypoxia is sensitive to seabed and bottom boundary layer processes. Results indicated that particulate organic matter remineralization in the bottom water column increased by an order of magnitude during resuspension events. This increased sediment oxygen consumption and ammonium production, which were defined as the sum of seabed fluxes of oxygen and ammonium, plus oxygen consumption and ammonium production in the water column due to resuspended organic matter. The increases in remineralization impacted biogeochemical dynamics to a greater extent than resuspension‐induced seabed fluxes and oxidation of reduced chemical species. The effect of resuspension on bottom water biogeochemistry increased with particulate organic matter availability, which was modulated by sediment transport patterns. Overall, when averaged over the shelf and on timescales of a month in the numerical model, cycles of erosion and deposition accounted for about two thirds of sediment oxygen consumption and almost all of the sediment ammonium production.
A Color‐Index‐Based Empirical Algorithm for Determining Particulate Organic Carbon Concentration in the Ocean From Satellite Observations
Authors: Le Chengfeng , Zhou Xueying , Hu Chuanmin , Lee Zhongping , Li Lin , Stramski Dariusz 
Published: September 2018

AbstractAn empirical algorithm for estimating particulate organic carbon (POC) concentration in the surface ocean from satellite observations is formulated and validated using in situ POC data and remote‐sensing reflectance (Rrs) data obtained from match‐up satellite ocean color measurements. The algorithm builds upon the band‐difference algorithm concept, which was originally developed for estimating chlorophyll‐a concentration in clear waters. This algorithm utilizes three spectral bands centered approximately at 490, 550, and 670 nm to determine a color index (CIPOC), from which POC can be estimated from satellite measurements. For comparison, the blue‐green band‐ratio algorithm is also formulated using the same data set of in situ POC and satellite‐derived Rrs. Results show that the statistical parameters characterizing the differences between the satellite‐derived POC and matchup in situ POC are similar when the CIPOC and band ratio algorithms are applied to open ocean waters where the values of CIPOC are relatively low. In coastal waters where the values of CIPOC are generally higher, the statistical parameters of algorithm performance are better for the CIPOC algorithm. In addition, because the CIPOC algorithm is less sensitive to errors and noise in the satellite‐derived Rrs, the image quality obtained with this algorithm can be improved for both open‐ocean and coastal waters.
Net Modulation of Upper Ocean Thermal Structure by Typhoon Kalmaegi (2014)
Authors: Zhang Han , Wu Renhao , Chen Dake , Liu Xiaohui , He Hailun , Tang Youmin , Ke Daoxun , Shen Zheqi , Li Junde , Xie Juncheng , Tian Di , Ming Jie , Liu Fu , Zhang Dongna , Zhang Wenyan 
Published: September 2018

AbstractIn situ observation of a buoys/moorings array and a model simulation were used to study the modulation of upper ocean thermal structure by Typhoon Kalmaegi in September 2014. The inertial period signals were significant after forcing of Kalmaegi, but they did not account for the net heat change. Removing the inertial period signals showed that the net thermal response biased to the right of Kalmaegi's track. Vertical mixing caused surface cooling with an inverted‐cone structure and subsurface warming with a double‐wing structure. Net upwelling converted the left wing of the subsurface warming to cooling, while net downwelling warmed the upper ocean in front and on both sides of the net upwelling zone. Horizontal advection was not as important as vertical mixing and vertical advection in modulating the thermal structure but contributed to the net outward advection of thermal anomaly in the mixed layer during the forced stage and also in the net along‐track recovery of subsurface anomaly during the relaxation stage. In general, horizontal and vertical advection modulated thermal anomalies in the upper ocean across a broader horizontal range and into the deeper ocean compared with the effect of vertical mixing. Our results indicate the need to consider both mixing and advection (rather than only mixing) when studying the effects of tropical cyclones on local ocean heat uptake and global ocean heat transport.
The Competing Effects of Breaking Waves on Surfzone Heat Fluxes: Albedo Versus Wave Heating
Authors: Sinnett Gregory , Feddersen Falk 
Published: September 2018

AbstractDepth‐limited wave breaking modifies the heat flux in the surfzone relative to the inner‐shelf (where waves are not breaking). Surfzone wave breaking generates heat through viscous dissipation (wave heating), but also increases surface foam coverage and albedo, thereby reducing solar heating, that is, cooling relative to the inner‐shelf. These two competing breaking wave effects are quantified with a yearlong experiment at the Scripps Institution of Oceanography Pier. Cross‐shore averaged surfzone albedo estimates were more than three times higher than inner‐shelf albedo, reducing the yearly averaged surfzone water‐entering shortwave radiation by 41 W/m2 relative to the inner‐shelf. Surfzone breaking wave dissipation added an additional yearly averaged 28 W/m2 relative to the inner‐shelf. The albedo‐induced solar heating reduction in spring, summer, and fall was usually greater than the wave heating. However, in winter, large waves and relatively weak shortwave solar radiation (due to both lower top of the atmosphere solar radiation and clouds) resulted in a nearly equal number of days of breaking wave‐induced heating or cooling. These two heat flux terms are coupled via wave breaking dissipation. Averaged over the surfzone, the albedo‐induced solar radiation reduction is linearly related to the downwelling solar radiation and is independent of wave height. Consequently, the albedo‐induced cooling to wave heating ratio is a function of breaking wave height to the −3/2 power, allowing evaluation of the relative importance of these terms in other geographic regions.
Preface to the Special Section: Dense Water Formations in the Northwestern Mediterranean: From the Physical Forcings to the Biogeochemical Consequences
Authors: Conan Pascal , Testor Pierre , Estournel Claude , D'Ortenzio Fabrizio , Pujo‐Pay Mireille , Durrieu de Madron Xavier 
Published: September 2018

AbstractThe northwestern Mediterranean Sea is one of the few sites of open‐sea deep convection and dense water formation. The area is characterized by intense air‐sea exchanges favored by the succession of strong northerly and northwesterly winds during autumn and winter that eventually induce deep convection episodes and the formation of the Western Mediterranean Deep Water. This region exhibits a significant spring phytoplankton bloom, which appears to be largely influenced in intensity and diversity by the winter mixing. To understand and resolve the interplay between the atmosphere and ocean, and the impact of ocean circulation and mixing on biogeochemistry, we carried out an unprecedented observational effort during a large experiment between July 2012 and July 2013. A multiplatform approach—combining aircraft, balloons, ships, moorings, floats, and gliders ‐ aimed both at characterizing the dynamics of the atmosphere and at quantifying the physical, biogeochemical, and biological properties of the water masses. Beyond a better understanding of the wind dynamics, the interannual variability of the deep convection, and the seasonal variability of the nutrient distribution and plankton structure in the pelagic ecosystem, the experiment provided a reference data set that was used as a benchmark for advancing the modeling of the surface fluxes, convective processes, dense water formation rates, and physical‐biogeochemical coupling processes. It also represented an opportunity for complementary investigations such as evaluating model parameterizations or studying the role of submesoscale eddies in dense water spreading and biogeochemistry.
The Characteristics and Mechanism of the Formation of Earth‐Air Pulsation in Extremely Arid Areas
Authors: Li Hongshou , Zhan Hongtao 
Published: September 2018

AbstractThe term earth‐air refers to the air inside the vadose zone. The observation of earth‐air was called hou‐qi, which was used to enact meter calendar in ancient China. Currently, however, as a detailed knowledge of hou‐qi has been lost for a long time, it has been denounced as a pseudoscience, as earth‐air is not scientifically and systematically monitored, and its characteristics and formation mechanism are unclear. We have attempted to scientifically monitor and measure earth‐air pressure and reveal its formation mechanism. Results from a specially devised set of air pressure measurements show that the pressure exhibits daily and yearly pulses at different depths. The main cause of the pulsation is soil temperature variation, which results in the soil‐combined water decomposing and air pressurization in warming, and water vapor recombining and air depressurization when cooling, leading to pulsation of the air pressure in the soil. Therefore, rather than a myth, hou‐qi has great significance in the geosciences and studies of the ancient Chinese civilization.
Airborne Observations of Reactive Inorganic Chlorine and Bromine Species in the Exhaust of Coal‐Fired Power Plants
Authors: Lee Ben H. , Lopez‐Hilfiker Felipe D. , Schroder Jason C. , Campuzano‐Jost Pedro , Jimenez Jose L. , McDuffie Erin E. , Fibiger Dorothy L. , Veres Patrick R. , Brown Steven S. , Campos Teresa L. , Weinheimer Andrew J. , Flocke Frank F. , Norris Gary , O'Mara Kate , Green Jaime R. , Fiddler Marc N. , Bililign Solomon , Shah Viral , Jaeglé Lyatt , Thornton Joel A. 
Published: September 2018

AbstractWe present airborne observations of gaseous reactive halogen species (HCl, Cl2, ClNO2, Br2, BrNO2, and BrCl), sulfur dioxide (SO2), and nonrefractory fine particulate chloride (pCl) and sulfate (pSO4) in power plant exhaust. Measurements were conducted during the Wintertime INvestigation of Transport, Emissions, and Reactivity campaign in February–March of 2015 aboard the NCAR‐NSF C‐130 aircraft. Fifty air mass encounters were identified in which SO2 levels were elevated ~5 ppb above ambient background levels and in proximity to operational power plants. Each encounter was attributed to one or more potential emission sources using a simple wind trajectory analysis. In case studies, we compare measured emission ratios to those reported in the 2011 National Emissions Inventory and present evidence of the conversion of HCl emitted from power plants to ClNO2. Taking into account possible chemical conversion downwind, there was general agreement between the observed and reported HCl:SO2 emission ratios. Reactive bromine species (Br2, BrNO2, and/or BrCl) were detected in the exhaust of some coal‐fired power plants, likely related to the absence of wet flue gas desulfurization emission control technology. Levels of bromine species enhanced in some encounters exceeded those expected assuming all of the native bromide in coal was released to the atmosphere, though there was no reported use of bromide salts (as a way to reduce mercury emissions) during Wintertime INvestigation of Transport, Emissions, and Reactivity observations. These measurements represent the first ever in‐flight observations of reactive gaseous chlorine and bromine containing compounds present in coal‐fired power plant exhaust.
Geologic History of the Northern Portion of the South Pole‐Aitken Basin on the Moon
Authors: Ivanov M. A. , Hiesinger H. , van der Bogert C. H. , Orgel C. , Pasckert J. H. , Head J. W. 
Published: September 2018

AbstractWe conducted a detailed photogeological analysis of the northern portion of the South Pole‐Aitken (SPA) basin (10–60°S, 125–175°W) and compiled a geological map (1:500,000 scale) of this region. Our new absolute model age for the Apollo basin, 3.98 + 0.04/−0.06 Ga, provides a lower age limit for the formation of the SPA basin. Some of the plains units in the study area were formed by distal ejecta from remote craters and basins. The characteristic concentrations of FeO and TiO2 of other plains are indicative of their volcanic origin. The oldest volcanic materials occur near the center of the SPA basin and have an Early Imbrian age of ~3.80 + 0.02/−0.02 Ga. Late Imbrian volcanic activity occurred in and around the Apollo basin. In total, the volcanic plains cover ~8% of the map area and cannot account for the extensive SPA iron signature. The sources of the signature are the oldest materials on the SPA floor (FeO ~11–14.5 wt%). In contrast, the ejecta composing the SPA rim are significantly poorer in FeO (<7.5 wt%). The signature could be related to the differentiation of the SPA impact melt. However, the spatial segregation of the ancient iron‐rich and iron‐poor materials suggests that the SPA iron signature predated the basin. Thus, the signature might be explained by a pre‐SPA lunar crust that was stratified with respect to the iron concentrations, so that the SPA impact excavated the upper, iron‐poorer portion of the crust to form the SPA rim and exposed the deeper, iron‐richer portion on the floor of the basin.
Polarimetry of Water Ice Particles Providing Insights on Grain Size and Degree of Sintering on Icy Planetary Surfaces
Authors: Poch O. , Cerubini R. , Pommerol A. , Jost B. , Thomas N. 
Published: September 2018

AbstractThe polarimetry of the light scattered by planetary surfaces is a powerful tool to provide constraints on their microstructure. To improve the interpretation of polarimetric data from icy surfaces, we have developed the POLarimeter for ICE Samples complementing the measurement facilities of the Ice Laboratory at the University of Bern. The new setup uses a high precision Stokes polarimeter to measure the degree of polarization in the visible light scattered by surfaces at moderate phase angles (from 1.5° to 30°). We present the photometric and polarimetric phase curves measured on various surfaces made of pure water ice particles having well‐controlled size and shape (spherical, crushed, and frost). The results show how the amplitude and the shape of the negative polarization branch change with the particles sizes and the degree of metamorphism of the ice. We found that fresh frost formed by water condensation on cold surfaces has a phase curve characterized by resonances (Mie oscillations) indicating that frost embryos are transparent micrometer‐sized particles with a narrow size distribution and spherical shape. Comparisons of these measurements with polarimetric observations of the icy satellites of the Solar System suggest that Europa is possibly covered by relatively coarser (~40–400 μm) and more sintered grains than Enceladus and Rhea, more likely covered by frost‐like particles of few micrometers in average. The great sensitivity of polarization to grain size and degree of sintering makes it an ideal tool to detect hints of ongoing processes on icy planetary surfaces, such as cryovolcanism.
An Ionosphere Specification Technique Based on Data Ingestion Algorithm and Empirical Orthogonal Function Analysis Method
Authors: Aa Ercha , Ridley Aaron , Huang Wengeng , Zou Shasha , Liu Siqing , Coster Anthea J. , Zhang Shunrong 
Published: September 2018

AbstractA data ingestion method in reproducing ionospheric electron density and total electron content (TEC) was developed to incorporate TEC products from the Madrigal Database into the NeQuick 2 model. The method is based on retrieving an appropriate global distribution of effective ionization parameter (Az) to drive the NeQuick 2 model, which can be implemented through minimizing the difference between the measured and modeled TEC at each grid in the local time‐modified dip latitude coordinates. The performance of this Madrigal TEC‐driven‐NeQuick 2 result is validated through the comparison with various International Global Navigation Satellite Systems Services global ionospheric maps and ionosonde data. The validation results show that a general accuracy improvement of 30–50% can be achieved after data ingestion. In addition, the empirical orthogonal function (EOF) analysis technique is used to construct a parameterized time‐varying global Az model. The quick convergence of EOF decomposition makes it possible to use the first six EOF series to represent over 90% of the total variances. The intrinsic diurnal variation and spatial distribution in the original data set can be well reflected by the constructed EOF base functions. The associated EOF coefficients can be expressed as a set of linear functions of F10.7 and Ap indices, combined with a series of trigonometric functions with annual/seasonal variation components. The NeQuick TEC driven by EOF‐modeled Az shows 10–15% improvement in accuracy over the standard ionosphere correction algorithm in the Galileo navigation system. These preliminary results demonstrate the effectiveness of the combined data ingestion and EOF modeling technique in improving the specifications of ionospheric density variations.
Establishment of stable iPS-derived human neural stem cell lines suitable for cell therapies
Authors: Rosati Jessica , Ferrari Daniela , Altieri Filomena , Tardivo Silvia , Ricciolini Claudia , Fusilli Caterina , Zalfa Cristina , Profico Daniela C. , Pinos Francesca , Bernardini Laura , Torres Barbara , Manni Isabella , Piaggio Giulia , Binda Elena , Copetti Massimiliano , Lamorte Giuseppe , Mazza Tommaso , Carella Massimo , Gelati Maurizio , Valente Enza Maria , Simeone Antonio , Vescovi Angelo L. 
Published: September 2018

AbstractEstablishing specific cell lineages from human induced pluripotent stem cells (hiPSCs) is vital for cell therapy approaches in regenerative medicine, particularly for neurodegenerative disorders. While neural precursors have been induced from hiPSCs, the establishment of hiPSC-derived human neural stem cells (hiNSCs), with characteristics that match foetal hNSCs and abide by cGMP standards, thus allowing clinical applications, has not been described. We generated hiNSCs by a virus-free technique, whose properties recapitulate those of the clinical-grade hNSCs successfully used in an Amyotrophic Lateral Sclerosis (ALS) phase I clinical trial. Ex vivo, hiNSCs critically depend on exogenous mitogens for stable self-renewal and amplification and spontaneously differentiate into astrocytes, oligodendrocytes and neurons upon their removal. In the brain of immunodeficient mice, hiNSCs engraft and differentiate into neurons and glia, without tumour formation. These findings now warrant the establishment of clinical-grade, autologous and continuous hiNSC lines for clinical trials in neurological diseases such as Huntington’s, Parkinson’s and Alzheimer’s, among others.
Forward models demonstrate that repetition suppression is best modelled by local neural scaling
Authors: Alink Arjen , Abdulrahman Hunar , Henson Richard N. 
Published: September 2018

AbstractInferring neural mechanisms from functional magnetic resonance imaging (fMRI) is challenging because the fMRI signal integrates over millions of neurons. One approach is to compare computational models that map neural activity to fMRI responses, to see which best predicts fMRI data. We use this approach to compare four possible neural mechanisms of fMRI adaptation to repeated stimuli (scaling, sharpening, repulsive shifting and attractive shifting), acting across three domains (global, local and remote). Six features of fMRI repetition effects are identified, both univariate and multivariate, from two independent fMRI experiments. After searching over parameter values, only the local scaling model can simultaneously fit all data features from both experiments. Thus fMRI stimulus repetition effects are best captured by down-scaling neuronal tuning curves in proportion to the difference between the stimulus and neuronal preference. These results emphasise the importance of formal modelling for bridging neuronal and fMRI levels of investigation.