bluuebunny/crossref_metadata_2025_split huggingface dataset:
MIPAS observations of longitudinal oscillations in the mesosphere and the lower thermosphere: climatology of odd-parity daily frequency modes
Authors: García-Comas Maya , González-Galindo Francisco , Funke Bernd , Gardini Angela , Jurado-Navarro Aythami , López-Puertas Manuel , Ward William E. 
Published: September 2016

Abstract. MIPAS global Sun-synchronous observations are almost fixed in local time. Subtraction of the descending and ascending node measurements at each longitude only includes the longitudinal oscillations with odd daily frequencies nodd from the Sun's perspective at 10:00. Contributions from the background atmosphere, daily-invariant zonal oscillations and tidal modes with even-parity daily frequencies vanish. We have determined longitudinal oscillations in MIPAS temperature with nodd and wavenumber k = 0–4 from the stratosphere to 150 km from April 2007 to March 2012. To our knowledge, this is the first time zonal oscillations in temperature have been derived pole to pole in this altitude range from a single instrument. The major findings are the detection of (1) migrating tides at northern and southern high latitudes; (2) significant k = 1 activity at extratropical and high latitudes, particularly in the Southern Hemisphere; (3) k = 3 and k = 4 eastward-propagating waves that penetrate the lower thermosphere with a significantly larger vertical wavelength than in the mesosphere; and (4) a migrating tide quasi-biennial oscillation in the stratosphere, mesosphere and lower thermosphere. MIPAS global measurements of longitudinal oscillations are useful for testing tide modeling in the mesosphere and lower thermosphere region and as a lower boundary for models extending higher up in the atmosphere.
Evaluation of water vapour assimilation in the tropical upper troposphere
and lower stratosphere by a chemical transport model
Authors: Payra Swagata , Ricaud Philippe , Abida Rachid , El Amraoui Laaziz , Attié Jean-Luc , Rivière Emmanuel , Carminati Fabien , von Clarmann Thomas 
Published: September 2016

Abstract. The present analysis deals with one of the most debated aspects of the studies on the upper troposphere/lower stratosphere (UTLS), namely the budget of water vapour (H2O) at the tropical tropopause. Within the French project “Multiscale water budget in the upper troposphere and lower stratosphere in the TROpics” (TRO-pico), a global-scale analysis has been set up based on space-borne observations, models and assimilation techniques. The MOCAGE-VALENTINA assimilation tool has been used to assimilate the Aura Microwave Limb Sounder (MLS) version 3.3 H2O measurements within the 316–5 hPa range from August 2011 to March 2013 with an assimilation window of 1 h. Diagnostics based on observations minus analysis and forecast are developed to assess the quality of the assimilated H2O fields. Comparison with an independent source of H2O measurements in the UTLS based on the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations and with meteorological ARPEGE analyses is also shown. Sensitivity studies of the analysed fields have been performed by (1) considering periods when no MLS measurements are available and (2) using H2O data from another MLS version (4.2). The studies have been performed within three different spaces in time and space coincidences with MLS (hereafter referred to as MLS space) and MIPAS (MIPAS space) observations and with the model (model space) outputs and at three different levels: 121 hPa (upper troposphere), 100 hPa (tropopause) and 68 hPa (lower stratosphere) in January and February 2012. In the MLS space, the analyses behave consistently with the MLS observations from the upper troposphere to the lower stratosphere. In the model space, the analyses are wetter than the reference atmosphere as represented by ARPEGE and MLS in the upper troposphere (121 hPa) and around the tropopause (100 hPa), but are consistent with MLS and MIPAS in the lower stratosphere (68 hPa). In the MIPAS space, the sensitivity and the vertical resolution of the MIPAS data set at 121 and 100 hPa prevent assessment of the behaviour of the analyses at 121 and 100 hPa, particularly over intense convective areas as the South American, the African and the Maritime continents but, in the lower stratosphere (68 hPa), the analyses are very consistent with MIPAS. Sensitivity studies show the improvement on the H2O analyses in the tropical UTLS when assimilating space-borne measurements of better quality, particularly over the convective areas.
The Pollino 2012 seismic sequence: clues from continuous radon monitoring
Authors: Piersanti Antonio , Cannelli Valentina , Galli Gianfranco 
Published: September 2016

Abstract. The 2012 Pollino (Calabria, Italy) seismic sequence, culminating in the Mw 5.2 earthquake of 25 October 2012, is investigated, exploiting data collected during a long-term continuous radon monitoring experiment performed in the epicentral area from late 2011 to the end of 2014. We analyse data collected both using a phenomenological approach based on quantitative evidence and a purely numerical analysis including the following: (i) correlation and cross-correlation investigations; (ii) an original approach aimed at limiting the impact of meteorological parameters variations on the interpretation of measured radon levels; (iii) a change point analysis; (iv) the implementation of an original detection algorithm aimed at highlighting the connections between radon emission variations and major seismic events occurrence. Results from both approaches suggest that radon monitoring stations can be subject to massive site effects, especially regarding rainfall, making data interpretation harder. The availability of long-term continuous measurements is crucial to precisely assess those effects. Nevertheless, statistical analysis shows a viable approach for quantitatively relating radon emanation variations to seismic energy release. Although much work is still needed to make radon time series analysis a robust complement to traditional seismological tools, this work has identified a characteristic variation in radon exhalation during the preparation process of large earthquakes.
Simultaneous quantification of depolymerization and mineralization rates by a novel 15N tracing model
Authors: Andresen Louise C. , Björsne Anna-Karin , Bodé Samuel , Klemedtsson Leif , Boeckx Pascal , Rütting Tobias 
Published: September 2016

Abstract. The depolymerization of soil organic matter, such as proteins and (oligo-)peptides, into monomers (e.g. amino acids) is currently considered to be the rate-limiting step for nitrogen (N) availability in terrestrial ecosystems. The mineralization of free amino acids (FAAs), liberated by the depolymerization of peptides, is an important fraction of the total mineralization of organic N. Hence, the accurate assessment of peptide depolymerization and FAA mineralization rates is important in order to gain a better process-based understanding of the soil N cycle. In this paper, we present an extended numerical 15N tracing model Ntrace, which incorporates the FAA pool and related N processes in order to provide a more robust and simultaneous quantification of depolymerization and gross mineralization rates of FAAs and soil organic N. We discuss analytical and numerical approaches for two forest soils, suggest improvements of the experimental work for future studies, and conclude that (i) when about half of all depolymerized peptide N is directly mineralized, FAA mineralization can be as important a rate-limiting step for total gross N mineralization as peptide depolymerization rate; (ii) gross FAA mineralization and FAA immobilization rates can be used to develop FAA use efficiency (NUEFAA), which can reveal microbial N or carbon (C) limitation.
Fabrication of efficient thermoacoustic device with an interdigitated-like electrode on indium tin oxide glass
Authors: Tsai Ming-shan , Yang Ko-kang , Chen Sy-hann , Ting Chen-ching , Jiang I-min 
Published: September 2016

Abstract
A thermoacoustic device was fabricated on indium tin oxide (ITO) glass, exhibiting an interdigitated-like electrode pattern. Our fabrication method enhanced the sound performance by approximately 20 dB compared with that of plain ITO film. Two approaches were adopted in this study to enhance the sound pressure level (SPL). One was to decrease the heat capacity per unit area of the device by reducing the thickness of the conductor film, and the other was to increase the thermal diffusivity of the device by applying a thin Au film on the electrode. We observed that heat generated by electron accumulation on ITO protrusions resulted in a large temperature oscillation of the surroundings and induced an SPL increase. A 4 nm Au film coating on the fabricated thermoacoustic device assisted thermal energy exchange with close-proximity air, improving the efficiency by an SPL of 7 dB.
MODOS DE VER A DOCÊNCIA ENTRE LICENCIANDAS DA UFPB
Authors: Sardelich Maria Emilia 
Published: September 2016

Este artigo tem por objetivo dar visibilidade às representações da docência que estão se construindo em um contexto de desprofissionalização e excesso de informação/imagens que afetam nossos modos de pensar, agir e aprender, entre licenciandas da Universidade Federal da Paraíba (UFPB). A investigação situa-se no âmbito da Cultura Visual, compreendendo o visual como lugar de interação social, no qual transitam enunciados conflitantes em meio a processos de identificação. Os resultados apontam para uma visualidade comum atrelada à missão docente vocacional. Junto a essa visualidade comum emerge outra que consideramos transgressora, sinalizando outro modo de ver, fazer ver e ver-se na docência.
Tree population dynamics on a floodplain: A tradeoff between tree mortality and seedling recruitment induced by stochastic floods
Authors: Miyamoto Hitoshi , Kimura Ryo 
Published: September 2016

AbstractThis paper proposes a stochastic evaluation method for examining tree population states in a river cross section using an integrated model with Monte Carlo simulation. The integrated model consists of four processes as submodels, i.e., tree population dynamics, flow discharge stochasticity, stream hydraulics, and channel geomorphology. A floodplain of the Kako River in Japan was examined as a test site, which is currently well vegetated and features many willows that have been growing in both individual size and overall population over the last several decades. The model was used to stochastically evaluate the effects of hydrologic and geomorphologic changes on tree population dynamics through the Monte Carlo simulation. The effects including the magnitude of flood impacts and the relative change in the floodplain level are examined using very simple scenarios for flow regulation, climate change, and channel form changes. The stochastic evaluation method revealed a tradeoff point in floodplain levels, at which the tendency of a fully vegetated state switches to that of a bare floodplain under small impacts of flood. It is concluded from these results that the states of tree population in a floodplain can be determined by the mutual interactions among flood impacts, seedling recruitment, tree growth, and channel geomorphology. These interactions make it difficult to obtain a basic understanding of tree population dynamics from a field study of a specific floodplain. The stochastic approach used in this paper could constitute an effective method for evaluating fundamental channel characteristics for a vegetated floodplain.
The causes of the hardest electron precipitation events seen with SAMPEX
Authors: Smith David M. , Casavant Eric P. , Comess Max D. , Liang Xinqing , Bowers Gregory S. , Selesnick Richard S. , Clausen Lasse B. N. , Millan Robyn M. , Sample John G. 
Published: September 2016

AbstractWe studied the geomagnetic, plasmaspheric, and solar wind context of relativistic electron precipitation (REP) events seen with the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), Proton Electron Telescope (PET) to derive an exponential folding energy E0 for each event. Events with E0< 400 keV peak near midnight, and with increasing E0, the peak magnetic local time (MLT) moves earlier but never peaks as early as the MLT distribution of electromagnetic ion cyclotron (EMIC) waves in the outer belt, and a distinct component near midnight remains. Events with E0>750 keV near dusk (1400 < MLT < 2000) show correlations with solar wind dynamic pressure and proton density, AE index, negative Dst index, and an extended plasmasphere, all supporting an EMIC wave interpretation. Events with 500 keV <E0< 600 keV near midnight (MLT 2200–0200) do not show these correlations. Comparing these two samples to all events with E0>500 keV (“hard REP”), we estimate that roughly 45% of the whole population has the distributions of geomagnetic and solar wind parameters associated with EMIC waves, while 55% does not. We hypothesize that the latter events may be caused by current sheet scattering (CSS), which can be mistaken for EMIC wave scattering in that both simultaneously precipitate MeV electrons and keV protons. Since a large number of MeV electrons are lost in the near‐midnight hard REP events, and in the large number of E0< 400 keV events that show no dusk‐like peak at all, we conclude that CSS should be studied further as a possibly important loss channel for MeV electrons.
Multiscale equatorial electrojet turbulence: Energy conservation, coupling, and cascades in a baseline 2‐D fluid model
Authors: Hassan Ehab , Hatch D. R. , Morrison P. J. , Horton W. 
Published: September 2016

AbstractProgress in understanding the coupling between plasma instabilities in the equatorial electrojet based on a unified fluid model is reported. Simulations with parameters set to various ionospheric background conditions revealed properties of the gradient‐drift and Farley‐Buneman instabilities. Notably, sharper density gradients increase linear growth rates at all scales, whereas variations in cross‐field E × B drift velocity only affect small‐scale instabilities. A formalism defining turbulent fluctuation energy for the system is introduced, and the turbulence is analyzed within this framework. This exercise serves as a useful verification test of the numerical simulations and also elucidates the physics underlying the ionospheric turbulence. Various physical mechanisms involved in the energetics are categorized as sources, sinks, nonlinear transfer, and cross‐field coupling. The physics of the nonlinear transfer terms is studied to identify their roles in producing energy cascades, which explain the generation of small‐scale structures that are stable in the linear regime. The theory of two‐step energy cascading to generate the 3 m plasma irregularities in the equatorial electrojet is verified for the first time in the fluid regime. In addition, the nonlinearity of the system allows the possibility of an inverse energy cascade, potentially responsible for generating large‐scale plasma structures at the top of the electrojet as found in different rocket and radar observations.
A numerical study of the interhemispheric asymmetry of the equatorial ionization anomaly in solstice at solar minimum
Authors: Dang Tong , Luan Xiaoli , Lei Jiuhou , Dou Xiankang , Wan Weixing 
Published: September 2016

AbstractIn this study, the mechanisms of interhemispheric asymmetry of the equatorial ionization anomaly (EIA) in June solstice at solar minimum were investigated through a series of simulations using the Thermosphere Ionosphere Electrodynamics General Circulation Model. Our results indicate that the transequatorial neutral wind is the main cause of the interhemispheric asymmetry. The transequatorial wind transports plasma from the summer hemisphere to winter hemisphere, leading to an enhancement in the winter EIA crest. Meanwhile, the ion production and loss are also important factors in producing the EIA asymmetry through photochemical processes. The longitudinal variations of the EIA interhemispheric asymmetry are also explored through imposing each term of ion continuity equation longitudinally independent. Our term analysis results suggest that the neutral wind variation dominates the longitudinal patterns of the interhemispheric asymmetry, while the E × B drift and photochemical process contribute less.
On the fresh development of equatorial plasma bubbles around the midnight hours of June solstice
Authors: Ajith K. K. , Tulasi Ram S. , Yamamoto M. , Otsuka Y. , Niranjan K. 
Published: September 2016

AbstractUsing the 47 MHz Equatorial Atmosphere Radar (EAR) at Kototabang, Indonesia, the nocturnal evolution of equatorial plasma bubbles (EPBs) was examined during the moderate solar activity years 2011–2012. While the evolution of EPBs was mostly (86%) confined to post sunset hours (1900–2100 LT) during equinoxes, in contrast, the majority of EPBs (~71%) in June solstice found evolve around the midnight hours (2200–0300 LT). The mechanisms behind the fresh evolution of summer time midnight EPBs were investigated, for the first time, through SAMI2 model simulations with a realistic input of background ExB drift variation derived from CINDI IVM on board C/NOFS satellite. The term‐by‐term analysis of linear growth rate of RT instability indicates that the formation of high flux tube electron content height gradient (KF) (steep vertical gradient) region at higher altitudes is the key factor for the enhanced growth rate of RT instability. The responsible factors are discussed in light of relatively weak westward zonal electric field in the presence of equatorward neutral wind and bottomside recombination around the midnight hours of June solstice. The effects of neutral winds and weak westward electric fields on the uplift of equatorial F layer were examined separately using controlled SAMI2 simulations. The results indicate that relatively larger linear growth rate is more likely to occur around midnight during June solstice because of relatively weak westward electric field than other local times in the presence of equatorward meridional wind.
Mapping daily and seasonal evapotranspiration from irrigated crops using global climate grids and satellite imagery: Automation and methods comparison
Authors: Biggs Trent W. , Marshall Michael , Messina Alex 
Published: September 2016

AbstractThe surface energy balance algorithm for land (SEBAL) estimates land surface evapotranspiration (ET) from radiometric surface temperature (TR), but requires manual selection of calibration pixels, which can be impractical for mapping seasonal ET. Here pixel selection is automated and SEBAL implemented using global climate grids and satellite imagery. SEBAL is compared with the MOD16 algorithm, which uses remotely sensed data on vegetation condition to constrain reference ET from the Penman‐Monteith equation. The difference between the evaporative fraction (Λ, range 0–1) from SEBAL and six eddy flux correlation towers was less than 0.10 for three of six towers, and less than 0.24 for all towers. SEBAL ET was moderately sensitive to surface roughness length and implementation over regions smaller than ∼10,000 km2 provided lower error than larger regions. Pixel selection based on TR had similar errors as those based on a vegetation index. For maize, MOD16 had lower error in mean seasonal evaporative fraction (−0.02) compared to SEBAL Λ (0.23), but MOD16 significantly underestimated the evaporative fraction from rice (−0.52) and cotton fields (−0.67) compared with SEBAL (−0.09 rice, −0.09 cotton). MOD16 had the largest error over short crops in the early growing season when vegetation cover was low but land surface was wet. Temperature‐based methods like SEBAL can be automated and likely outperform vegetation‐based methods in irrigated areas, especially under conditions of low vegetation cover and high soil evaporation.
Pore‐space structure and average dissolution rates: A simulation study
Authors: Pereira Nunes J. P. , Bijeljic B. , Blunt M. J. 
Published: September 2016

AbstractWe study the influence of the pore‐space geometry on sample‐averaged dissolution rates in millimeter‐scale carbonate samples undergoing reaction‐controlled mineral dissolution upon the injection of a
‐saturated brine. The representation of the pore space is obtained directly from micro‐CT images with a resolution of a few microns. Simulations are performed with a particle tracking approach on images of three porous rocks of increasing pore‐space complexity: a bead pack, a Ketton oolite, and an Estaillades limestone. Reactive transport is simulated with a hybrid approach that combines a Lagrangian method for transport and reaction with the Eulerian flow field obtained by solving the incompressible Navier‐Stokes equations directly on the voxels of three‐dimensional images. Particle advection is performed with a semianalytical streamline method and diffusion is simulated via a random walk. Mineral dissolution is defined in terms of the particle flux through the pore‐solid interface, which can be related analytically to the batch (intrinsic) reaction rate. The impact of the flow heterogeneity on reactive transport is illustrated in a series of simulations performed at different flow rates. The average dissolution rates depend on both the heterogeneity of the sample and on the flow rate. The most heterogeneous rock may exhibit a decrease of up to two orders of magnitude in the sample‐averaged reaction rates in comparison with the batch rate. Furthermore, we provide new insights for the dissolution regime that would be traditionally characterized as uniform. In most cases, at the pore‐scale, dissolution preferentially enlarges fast‐flow channels which greatly restricts the effective surface available for reaction.
Side draw optimisation of a high‐purity, multi‐component distillation column
Authors: Kraller Michael A. , Udugama Isuru A. , Kirkpatrick Robert , Yu Wei , Young Brent R. 
Published: September 2016

AbstractDistillation columns with side draws are widely used in the process industry to refine crude methanol into high‐purity methanol. Historically, industrial methanol manufacturers have concentrated on meeting strict product specifications, while methanol yield and reboiler duty optimisation has often been neglected. In this work, a steady‐state model of an industrial high‐purity multi‐component methanol distillation column was developed using a commercial process simulator. To achieve higher recovery at optimal reboiler duty, the side draw location and side draw mass flow rates were identified as two important factors. It was determined that a combination of lowering the side draw location while reducing the side draw mass flow rate will lead to the most optimal outcome. A design of experiment was also carried out to evaluate the stability of the column at recovery rates of 97.7% (current recovery) and 99.5% (proposed high recovery). Disturbances in the feed stream were identified as having the greatest effect, while the product purity was observed to become more sensitive towards all disturbances when operating at an enhanced recovery. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.
How NOAA's Office of National Marine Sanctuaries engages the public in the ocean through the science and management of maritime heritage
Authors: Delgado James P. , Van Tilburg Hans K. , Terrell Bruce G. , Marx Deborah , Marzin Catherine , Gittings Stephen , Kiene William , Grussing Valerie , Orlando Pamela 
Published: September 2016

Abstract

The US Office of National Marine Sanctuaries has a robust Maritime Heritage Program (MHP), now 13 years old.
MHP is a carefully created and managed part of an overall strategy to encourage ocean conservation and the creation of marine protected areas.
MHP utilizes a variety of strategies to engage the public, work collaboratively, and use the power of ‘people stories’ to connect a wide audience with the ocean.
Published 2016. This article is a U.S. Government work and is in the public domain in the USA.