bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deformation in the Northern Volcanic Zone of Iceland 2008–2014: An interplay of tectonic, magmatic, and glacial isostatic deformation
Authors: Drouin Vincent , Sigmundsson Freysteinn , Ófeigsson Benedikt G. , Hreinsdóttir Sigrún , Sturkell Erik , Einarsson Páll 
Published: March 2017

AbstractGPS measurements spanning 2008 to 2014 are used to derive the surface velocity field across the Northern Volcanic Zone (NVZ) of Iceland, a subaerial part of the divergent boundary between the North American and Eurasian plates. No volcanic activity nor magmatic intrusions were detected in the zone during this time period. We infer an extensional rate of 17.4
mm/yr in direction 292.0
°, consistent with the results of previous studies and current plate motion models including MORVEL2010 and GEODVEL2010. The horizontal velocity field reveals about 50 km wide stretching zone caused by the divergent plate movements. Glacial isostatic adjustment (GIA) induces uplift of over 20 mm/yr at the northern edge of Vatnajökull ice cap and 3–4 mm/yr horizontal motion directed away from the ice cap. Deformation in the NVZ between 2008 and 2014 can be reproduced by a combination of models relating to several different processes: (i) Mogi sources for volcanic and geothermal deformation at the Askja and Krafla volcanoes, (ii) scaled version of a velocity field derived from a glacial isostatic model, and (iii) simple arctangent‐based model for secular plate spreading. We find the approximate location of the plate boundary spreading axis as well as its locking depth. The spreading axis lies through the Krafla, Fremrinámar, and Askja central volcanoes, the most active ones in the NVZ. It does not appear to follow the general direction of each fissure swarm but rather to change direction at the central volcanoes. The locking depth is on average within the 7–9 km range.
Do dust emissions from sparsely vegetated regions dominate atmospheric iron supply to the Southern Ocean?
Authors: Ito Akinori , Kok Jasper F. 
Published: March 2017

AbstractAtmospheric deposition of dust aerosols is a significant source of exogenous iron (Fe) in marine ecosystems and is critical in setting primary marine productivity during summer. This dust‐borne input of Fe is particularly important to the Southern Ocean, which is arguably the most biogeochemically important ocean because of its large spatial extent and its considerable influence on the global carbon cycle. However, there is large uncertainty in estimates of dust emissions in the Southern Hemisphere and thus of the deposition of Fe‐containing aerosols onto oceans. Here we hypothesize that sparsely vegetated surfaces in arid and semiarid regions are important sources of Fe‐containing aerosols to the Southern Ocean. We test this hypothesis using an improved dust emission scheme in conjunction with satellite products of vegetation cover and soil moisture in an atmospheric chemistry transport model. Our improved model shows a twofold increase of Fe input into the Southern Ocean in austral summer with respect to spring and estimates that the Fe input is more than double that simulated using a conventional dust emission scheme in summer. Our model results suggest that dust emissions from open shrublands contribute over 90% of total Fe deposition into the Southern Ocean. These findings have important implications for the projection of the Southern Ocean's carbon uptake.
Bias adjustment of infrared‐based rainfall estimation using Passive Microwave satellite rainfall data
Authors: Karbalaee Negar , Hsu Kuolin , Sorooshian Soroosh , Braithwaite Dan 
Published: March 2017

AbstractThis study explores using Passive Microwave (PMW) rainfall estimation for spatial and temporal adjustment of Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks‐Cloud Classification System (PERSIANN‐CCS). The PERSIANN‐CCS algorithm collects information from infrared images to estimate rainfall. PERSIANN‐CCS is one of the algorithms used in the Integrated Multisatellite Retrievals for GPM (Global Precipitation Mission) estimation for the time period PMW rainfall estimations are limited or not available. Continued improvement of PERSIANN‐CCS will support Integrated Multisatellite Retrievals for GPM for current as well as retrospective estimations of global precipitation. This study takes advantage of the high spatial and temporal resolution of GEO‐based PERSIANN‐CCS estimation and the more effective, but lower sample frequency, PMW estimation. The Probability Matching Method (PMM) was used to adjust the rainfall distribution of GEO‐based PERSIANN‐CCS toward that of PMW rainfall estimation. The results show that a significant improvement of global PERSIANN‐CCS rainfall estimation is obtained.
Effect of cloud microphysics on Indian summer monsoon precipitating clouds: A coupled climate modeling study
Authors: Hazra Anupam , Chaudhari Hemantkumar S. , Saha Subodh K. , Pokhrel Samir 
Published: March 2017

AbstractThe quest for one of the most dominant processes controlling the large‐scale circulations in the tropics is unraveled. The impact of cloud microphysical processes is known to have effects on rainfall and local atmospheric thermodynamics; however, its effect on the prevailing mean circulations is not yet studied. Two sets of coupled global climate model experiments (ICE and NO ICE microphysics) reveal that ice microphysics improves the strength of the Hadley circulation with respect to observation. Results pinpoint that ICE simulation enhances high cloud fraction (global tropics: ~59%, India: ~51%) and stratiform rain (global tropics: ~5%, India: ~15%) contribution. ICE and NO ICE cloud microphysics impacts differently on the outgoing longwave radiation (OLR), tropospheric temperature, and surface shortwave and longwave radiation. The effect of ice microphysics reduces OLR, which signifies deeper convection in the ICE run. The global annual average of the net radiation flux (shortwave and longwave) at the surface in ICE run (108.1 W/m2) is close to the observation (106 W/m2), which is overestimated in NO ICE run (112 W/m2). The result of apparent heat source term over the land and ocean surface eventually modifies regional Hadley circulation. Thus, the effect of ice microphysics in the global coupled model is important not only because of microphysics but also due to the radiation feedbacks. Therefore, better ice‐phase microphysics is required in the new generation of climate forecast model, which may lead to improvements in the simulation of monsoon.
Multiple satellite‐based analysis reveals complex climate effects of temperate forests and related energy budget
Authors: Ma Wei , Jia Gensuo , Zhang Anzhi 
Published: March 2017

AbstractForest conversion‐driven biophysical processes have been examined in various case studies that largely depend on sensitivity analysis of climate modeling. However, much remains unknown in the real world due to the complicated process and uncertainty in magnitude, especially in the temperate bioclimate regions. This study applied satellite‐based observation to investigate the biophysical climate response to potential forest conversion in China, especially on the spatial and temporal patterns and underlying mechanisms. We evaluated the differences of land surface temperature (ΔLST) between adjacent forest and cropland, in terms of the latitudinal and seasonal patterns. Compared to cropland, the temperate forest to the south of 40°N showed the cooling effect of −0.61 ± 0.02°C (95% confidence interval, and hereafter), and it presented the warming effect of 0.48 ± 0.06°C to the north of 48°N (the transition zone was between 40°N and 48°N). Seasonal analysis further demonstrated that the cooling effects of temperate forest in China in spring (March, April, May), summer (June, July, August), and autumn (September, October, November) were −0.53 ± 0.02°C, −0.55 ± 0.02°C, and −0.30 ± 0.02°C, respectively, while the forest caused the warming effect of 0.10 ± 0.04°C in winter (December, January, February). However, the biophysical climate response to forest conversion in temperate regions was complex and showed highly spatial and temporal heterogeneity. We further assessed the role of two major biophysical processes, i.e., albedo and evapotranspiration (ET), in shaping land surface temperature from surface energy budget perspective. Results showed that the latitudinal, seasonal, and spatiotemporal patterns of ΔLST was determined by the net effect of ET‐induced latent heat changes and albedo‐induced solar radiation absorption changes.
Increasing heat waves and warm spells in India, observed from a multiaspect framework
Authors: Panda Dileep Kumar , AghaKouchak Amir , Ambast Sunil Kumar 
Published: March 2017

AbstractRecent heat waves have been a matter of serious concern for India because of potential impacts on agriculture, food security, and socioeconomic progress. This study examines the trends and variability in frequency, duration, and intensity of hot episodes during three time periods (1951–2013, 1981–2013 and 1998–2013) by defining heat waves based on the percentile of maximum, minimum, and mean temperatures. The study also explores heat waves and their relationships with hydroclimatic variables, such as rainfall, terrestrial water storage, Palmer drought severity index, and sea surface temperature. Results reveal that the number, frequency, and duration of daytime heat waves increased considerably during the post‐1980 dry and hot phase over a large area. The densely populated and agriculturally dominated northern half of India stands out as a key region where the nighttime heat wave metrics reflected the most pronounced amplifications. Despite the recent warming hiatus in India and other parts of the world, we find that both daytime and nighttime extreme measures have undergone substantial changes during or in the year following a dry year since 2002, with the probability distribution functions manifesting a hotter‐than‐normal climate during 1998–2013. This study shows that a few months preceding the 2010 record‐breaking heat wave in Russia, India experienced the largest hot episode in the country's history. Interestingly, both these mega events are comparable in terms of their evolution and amplification. These findings emphasize the importance of planning for strategies in the context of the rising cooccurrence of dry and hot events.
Spatial domain indirect holographic technique for antenna near‐field phaseless measurements
Authors: Costanzo S. , Di Massa G. 
Published: March 2017

AbstractA spatial domain formulation of an indirect holographic technique, useful for antenna near‐field phase retrieval, is presented in this paper. The proposed approach is based on the adoption of three synthetic reference signals, giving three sets of amplitude‐only near‐field data. These are directly processed in the spatial domain to accurately retrieve the near‐field phase, from which the antenna radiation features can be subsequently computed. Despite the standard indirect holographic approach, no data processing is required in the spectral (Fourier transform) domain, thus completely avoiding the problem of spectrum overlapping which limits the accuracy of standard method. The effectiveness of the proposed technique is demonstrated by a numerical test on a linear dipole array, as well as by experimental results on a ridged‐horn antenna.
The variability of low‐latitude ionospheric amplitude and phase scintillation detected by a triple‐frequency GPS receiver
Authors: de Oliveira Moraes Alison , Costa Emanoel , Abdu Mangalathayil Ali , Rodrigues Fabiano S. , de Paula Eurico Rodrigues , Oliveira Kelias , Perrella Waldecir João 
Published: March 2017

AbstractIonospheric scintillation is a manifestation of space weather effects that seriously affect the performance and availability of space‐based navigation and communication systems. This paper presents results from an investigation on the characteristics of the phase and amplitude scintillation of Global Positioning System signals at the L1, L2C, and L5 frequencies. Field data obtained by a scintillation monitor installed in São José dos Campos (23.1°S, 45.8°W; dip latitude 17.3°S, declination 21.4°W), Brazil, a station located near the southern crest of the equatorial ionization anomaly, were used for this purpose. The analyzed data were collected during 150 nights from November 2014 to March 2015, an epoch of moderate solar activity close to the recent solar maximum. Only measurements corresponding to an elevation mask of 30° and values above standard threshold levels were used in the analysis. Outstanding characteristics of amplitude and phase scintillation are analyzed and compared in this study. The different characteristics of the scintillation focused in this study include (1) the statistics of their occurrences at the three frequencies; (2) the local time distributions of the amplitude and phase scintillation at different intensity levels; (3) azimuth‐elevation (spatial) distributions at different levels of the standard deviation of phase fluctuations; (4) scintillation enhancement and loss of phase lock conditions due to field‐aligned (longitudinal) propagation; (5) the relationship between amplitude and phase scintillation parameters for the L1, L2C, and L5 frequencies; and (6) the frequency dependence of the amplitude and phase scintillations. Important results on these different characteristics are presented and discussed, and some outstanding problems for future investigations are suggested.
Flare forecasting at the Met Office Space Weather Operations Centre
Authors: Murray S. A. , Bingham S. , Sharpe M. , Jackson D. R. 
Published: March 2017

AbstractThe Met Office Space Weather Operations Centre produces 24/7/365 space weather guidance, alerts, and forecasts to a wide range of government and commercial end‐users across the United Kingdom. Solar flare forecasts are one of its products, which are issued multiple times a day in two forms: forecasts for each active region on the solar disk over the next 24 h and full‐disk forecasts for the next 4 days. Here the forecasting process is described in detail, as well as first verification of archived forecasts using methods commonly used in operational weather prediction. Real‐time verification available for operational flare forecasting use is also described. The influence of human forecasters is highlighted, with human‐edited forecasts outperforming original model results and forecasting skill decreasing over longer forecast lead times.
Cloud heights measured by MISR from 2000 to 2015
Authors: Davies Roger , Jovanovic Veljko M. , Moroney Catherine M. 
Published: March 2017

AbstractDavies and Molloy (2012) reported a decrease in the global effective cloud height over the first 10 years of Multiangle Imaging Spectroradiometer (MISR) measurements on the Terra satellite. We have reexamined their time series for possible artefacts that might especially affect the initial portion of the record when the heights appeared anomalously high. While variations in sampling were shown to be inconsequential, an artefact due to the change in equator crossing time that affected the first 2 years was discovered, and this has now been corrected. That correction, together with the extension of the time series by five more years, yields no significant overall trend in global heights during the first 15 years of Terra operation. The time series is dominated by large interannual fluctuations associated with La Niña events that mask any overall trend on a global scale. On a regional basis, the cloud heights showed significant interannual variations of much larger amplitude, sometimes with fairly direct cancellation between regions. There were unexplained differences between the two hemispheres in the timing of height anomalies. These differences persisted over a large range of extratropical latitudes, suggestive of teleconnections. Within the tropics, there were very strong changes associated with the Central Pacific and Indonesian Maritime Continent regions that oscillated out of phase with each other, with interannual amplitudes that exceeded 1 km.
Graphite Furnace Atomic Absorption Spectrometry
Authors: Borges Daniel L.G. , Holcombe James A. 
Published: March 2017

Abstract
Atomic absorption spectrometry (AAS) enjoys excellent elemental selectivity and widespread usage with documented methodologies for a wide range of samples and matrices. Replacing the traditional flame atomizer with a graphite furnace (or ‘electrothermal atomizer (ETA)’) adds significantly to the flexibility of AAS and provides significantly lower detection limits. The basic principles of atomic absorption (AA) and the use of a graphite furnace as a means of generating the free atoms that are used in the spectrometric analysis are presented in this article. We must begin by understanding the basic chemical and physical transformations that occur from the moment a sample is placed on the graphite surface until the atomic vapors generated by heating of the graphite furnace diffuse from the tube and the absorption signal terminates. The path leading to the production of free gas‐phase atoms within the measurement volume within the graphite tube is a fascinating tale with many twists depending on sample and matrix. The chemical knowledge of various compounds has led to logical and innovative methodologies for particular analytes in specific matrices. All the efforts are in an attempt to permit interference‐free analyses using simple aqueous standards in the preparation of calibration curves. Limits of detection in the parts per billion range (picogram, absolute), microsampling capabilities, and methods for solids and slurries analysis have made this a popular analytical technique for ultratrace metal analysis.
Microfluidic Systems in Analytical Chemistry
Authors: Gómez‐Hens Agustina , Fernández‐Romero Juan M. 
Published: March 2017

AbstractThis article provides an overview of the evolution of the different strategies described to improve the performance of microfluidic systems applied in Analytical Chemistry. The concept of analytical microfluidics here encompasses different approaches designed to implement these miniaturized systems for analytical purposes. The physical phenomena involved in microfluidic systems and the microfabrication techniques and materials used in these systems are briefly described. The strategies and difficulties in integrating the different steps of the analytical process, including sample pretreatment, separation, and detection, on a single microfluidic device are discussed. This article includes the most recent trends in the development of microfluidic analytical systems, such as the availability of new biosensors, the analytical usefulness of paper‐based microfluidic systems, the use of nanotechnology, and the applicability of these miniaturized systems to biochemical, food, and environmental analysis.
Mass Spectrometry‐Based Electronic Nose for Bioanalysis
Authors: Pavón José Luis Pérez , del Nogal Sánchez Miguel , Ferreira Ana M.C. , Cordero Bernardo Moreno 
Published: March 2017

AbstractThe process used to solve many analytical problems involves obtaining information on isolated compounds. Sample treatment is the costliest and most time‐consuming part of the process and a frequent source of errors. However, sometimes it is not necessary to obtain information on individual compounds and profile signals are enough to make decisions. Here, electronic noses (e‐noses) are considered within the possibilities of non‐separative methods and specifically, electronic nose based on mass spectrometry (MS) in the bioanalysis field are discussed. These instrumental configurations are very attractive since sample treatment is eliminated or reduced and no chromatographic steps are required. Chemometric techniques are needed to extract the information from the signals.Endogenous volatile compounds provide important information about the state of the health of an individual and they can be analyzed with a MS‐based electronic nose. Their use in disease detection is, basically, the adaptation of an ancient practice in medicine.In this work the main instrumental configurations based on this approach and some applications in the bioanalysis field considering noninvasive biological fluids are described.
Trends for the Development of In Situ Analysis Devices
Authors: Jornet‐Martínez N. , Moliner‐Martínez Y. , Molins‐Legua C. , Campíns‐Falcó P. 
Published: March 2017

AbstractThe aim of this article is to review the analytical devices for in situ analysis developed in the last years. First, the concept in situ in the analytical context is defined. Then, the topic is addressed revising the issues that need to be considered for in situ analytical devices, their advantages compared with methods carried out at laboratory and the limitations associated to the methodologies and devices. In addition, illustrative examples of proposed in situ devices are shown, with special emphasis on optical‐based devices. Finally, the scientific, technological, and social factors involved in the development of the current devices are discussed. Moreover, the key trends that influence the future evolution of in situ analysis are highlighted.
Lewis Acid‐Catalyzed C(sp3)–C(sp3) Bond Forming Cyclization Reactions for the Synthesis of Tetrahydroprotoberberine Derivatives
Authors: Li Jianjun , Qin Cong , Yu Yang , Fan Huaqiang , Fu Yiwei , Li Hao , Wang Wei 
Published: March 2017

AbstractAn efficient Lewis acid‐catalyzed C(sp3)–C(sp3) bond forming annulation reaction has been developed. This strategy serves as a new method for the facile synthesis of tetrahydro‐5H‐isoquinolino[2,1‐g][1,6]naphthyridine derivatives. A wide range of 2‐methylquinoline‐3‐carbaldehydes and 1,2,3,4‐tetrahydroisoquinolines can be applied for this process to afford structurally diverse tetrahydroprotoberberine derivatives in excellent yields.magnified image
Influence of nitrogen plasma treatment on the wettability of polyetheretherketone and deposited chitosan layers
Authors: Terpiłowski Konrad , Wiącek Agnieszka Ewa , Jurak Małgorzata 
Published: March 2017

AbstractWettability properties of polyetheretherketone (PEEK) activated and non‐activated by nitrogen plasma have been investigated. Moreover, the PEEK plates were covered with antibacterial chitosan and its wettability properties were also investigated. Surface topography was determined using SEM and optical profilometry and surface composition by FT‐IR and XPS. For determination of apparent surface free energy, the hysteresis approach (CAH), acid base (LWAB), and Owens–Wendt (O–W) theory were used. The equilibrium contact angles were calculated from the Tadmor theory and further used for apparent surface energy calculation applying the above‐mentioned approaches. Due to the surface plasma activation both the roughness of the surface and the polar component of apparent surface free energy increased. It is shown that nitrogen plasma activation of PEEK surface increases the adhesion of chitosan to the surface due to the combination effect of: (i) the increase in surface roughness, (ii) introducing the polar groups onto the surface.