bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possibility to locate the position of the H2O snowline in protoplanetary disks through spectroscopic observations
Authors: Notsu Shota , Nomura Hideko , Walsh Catherine , Honda Mitsuhiko , Hirota Tomoya , Akiyama Eiji , Millar T. J. 
Published: September 2018

AbstractObservationally measuring the location of the H2O snowline is crucial for understanding the planetesimal and planet formation processes, and the origin of water on Earth. The velocity profiles of emission lines from protoplanetary disks are usually affected by Doppler shift due to Keplerian rotation and thermal broadening. Therefore, the velocity profiles are sensitive to the radial distribution of the line-emitting regions. In our work (Notsu et al. 2016, 2017), we found candidate water lines to locate the position of the H2O snowline through future high-dispersion spectroscopic observations. First, we calculated the chemical composition of the disks around a T Tauri star and a Herbig Ae star using chemical kinetics. We confirmed that the abundance of H2O gas is high not only in the hot midplane region inside the H2O snowline but also in the hot surface layer and the photodesorption region of the outer disk. The position of the H2O snowline in the Herbig Ae disk exists at a larger radius from the central star than that in the T Tauri disk. Second, we calculated the H2O line profiles and identified that H2O emission lines with small Einstein A coefficients (∼10−6 − 10−3 s−1) and relatively high upper state energies (∼ 1000K) are dominated by emission from the hot midplane region inside the H2O snowline, and therefore their profiles potentially contain information which can be used to locate the position of the H2O snowline. The wavelengths of the H2O lines which are the best candidates to locate the position of the H2O snowline range from mid-infrared to sub-millimeter, and the total line fluxes tend to increase with decreasing wavelengths. We investigated the possibility of future observations using the ALMA and mid-infrared high-dispersion spectrographs (e.g., SPICA/SMI-HRS). Since the fluxes of those identified lines from a Herbig Ae disk are stronger than those of a T Tauri disk, the possibility of a successful detection is expected to increase for a Herbig Ae disk.
100 GHz Room-Temperature Laboratory Emission Spectrometer
Authors: Wehres Nadine , Heyne Bettina , Lewen Frank , Hermanns Marius , Schmidt Bernhard , Endres Christian , Graf Urs U. , Higgins Daniel R. , Schlemmer Stephan 
Published: September 2018

AbstractWe present first results of a new heterodyne spectrometer dedicated to high-resolution spectroscopy of molecules of astrophysical importance. The spectrometer, based on a room-temperature heterodyne receiver, is sensitive to frequencies between 75 and 110 GHz with an instantaneous bandwidth of currently 2.5 GHz in a single sideband. The system performance, in particular the sensitivity and stability, is evaluated. Proof of concept of this spectrometer is demonstrated by recording the emission spectrum of methyl cyanide, CH3CN. Compared to state-of-the-art radio telescope receivers the instrument is less sensitive by about one order of magnitude. Nevertheless, the capability for absolute intensity measurements can be exploited in various experiments, in particular for the interpretation of the ever richer spectra in the ALMA era. The ease of operation at room-temperature allows for long time integration, the fast response time for integration in chirped pulse instruments or for recording time dependent signals. Future prospects as well as limitations of the receiver for the spectroscopy of complex organic molecules (COMs) are discussed.
Rings, rings, rings: what does CN tell us?
Authors: Cazzoletti Paolo 
Published: September 2018

AbstractCN emission lines are among the brightest, and have been observed in the last 20 years with single dish observations. With modern interferometers, we are now able to spatially resolve CN emission, which often shows ring-like structures. We investigate whether such structures trace the morphology of the disks, or if they have a chemical origin. By using the thermochemical code DALI, we conclude that CN formation is triggered by the existence of vibrationally excited H2*, produced by FUV pumping of H2. Herbig stars therefore generally have larger rings and higher CN fluxes than TTauri. Disks with higher masses and flaring also show stronger CN emission and larger rings. CN observations could in the future provide important constraints on some important disk physical parameters. The results of the models are well consistent with the spatially resolved CN observations to-date available.
The influence of chemical environment on the infrared spectra of embedded molecules in astrophysical ices
Authors: Bonfim Victor S. , Pilling Sergio 
Published: September 2018

AbstractIn this work, one intends to computationally simulate and investigate, via thermochemical calculations, how the chemical environment influences some molecular properties, such as IR spectra and absorption cross section, of individual species embedded in the solid phase employing the Polarized Continuum Model (PCM) approach. The trial molecules used here to check these effects are CO, CO2 and H2O. The solid phase (bulk ice) is simulated using different dielectric constant values representing different types of astrophysical ice at PCM approach. The effect of temperature is also investigated since it is known it affects the dielectric constant of the solvent medium.
Chemistry in velocity: Investigating gas chemical properties in 4D
Authors: Hacar Alvaro , van Dischoeck Ewine 
Published: September 2018

AbstractGas chemistry is typically characterized comparing integrated intensities of different molecular species. With the advent of ALMA, chemistry is now resolved not only in space but also in velocity. When observed at high spectral resolution, most of the clouds, filaments, and cores in the solar neighbourhood show a complex internal structure with multiple velocity components. This intrinsic complexity should be disentangled in order to correctly interpret their chemical properties. We present the first results of the FIVE+ analysis technique combining both state-of-the-art structure reconstruction (2D), kinematic decomposition (+1D), and chemical analysis (+1D) in large molecular datasets.
Surface astrochemistry: a computational chemistry perspective
Authors: Cuppen H. M. , Fredon A. , Lamberts T. , Penteado E. M. , Simons M. , Walsh C. 
Published: September 2018

AbstractMolecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. Especially, saturated, hydrogen-rich molecules are formed through surface chemistry. Astrochemical models have developed over the decades to understand the molecular processes in the interstellar medium, taking into account grain surface chemistry. However, essential input information for gas-grain models, such as binding energies of molecules to the surface, have been derived experimentally only for a handful of species, leaving hundreds of species with highly uncertain estimates. Moreover, some fundamental processes are not well enough constrained to implement these into the models.The proceedings gives three examples how computational chemistry techniques can help answer fundamental questions regarding grain surface chemistry.
Movement Institutions: The Bureaucratic Sources of Feminist Protest
Authors: Bereni Laure , Revillard Anne 
Published: September 2018

AbstractOver the past several decades, scholarship on women's movements, feminism, and the state has brought renewed attention to the study of protest politics by questioning its frontier with dominant institutions. This article takes this critique a step further by considering the institutional dimension of the state-movement intersection. Drawing on the French case, we argue that institutions that are formally devoted to women's rights inside the state (women's policy agencies) can operate as movement institutions—that is, as bureaucratic instances routinely engrained with a protest dimension—rather than being only a shelter for a network of insider activists. As such, they can provide a specific, institutional feminist socialization to their members; they can purvey, rather than only relay, feminist protest, and they can deploy institutional repertoires of protest, combining bureaucratic and movement dimensions. We conclude that the definition and boundaries of the women's movement need to be broadened to include bureaucratic sources of feminist protest.
Whistler Mode Waves Associated With Broadband Auroral Electron Precipitation at Jupiter
Authors: Kurth W. S. , Mauk B. H. , Elliott S. S. , Gurnett D. A. , Hospodarsky G. B. , Santolik O. , Connerney J. E. P. , Valek P. , Allegrini F. , Gladstone G. R. , Bolton S. J. , Levin S. M. 
Published: September 2018

AbstractLarge amplitude electromagnetic plasma waves are observed simultaneously with intense fluxes of electrons precipitating on auroral field lines at Jupiter. Here we present plasma wave observations from the Juno Waves instrument obtained during an instance of very intense broadband electron precipitation observed by the Jupiter Energetic Particle Detector Instrument connecting to Jupiter's main auroral oval. The wave spectrum extends from 50 Hz to ~10 kHz with peak‐to‐peak amplitudes of ~10 nT in the magnetic channel and of ~1 V/m in the electric channel, representing some of the most intense plasma waves observed by Juno. The E and B fields of these electromagnetic waves are correlated and have apparent polarization perpendicular to Jupiter's magnetic field with a downward Poynting flux. We conclude the plasma waves are whistler mode emissions with a possible admixture of ion‐cyclotron or Alfvén waves and may be important in the broadband electron acceleration.
Surface Temperature in Twentieth Century at the Styx Glacier, Northern Victoria Land, Antarctica, From Borehole Thermometry
Authors: Yang Ji‐Woong , Han Yeongcheol , Orsi Anaïs J. , Kim Seong‐Joong , Han Hyangsun , Ryu Yeongjun , Jang Youngjoon , Moon Jangil , Choi Taejin , Hur Soon Do , Ahn Jinho 
Published: September 2018

AbstractReconstruction of the long‐term surface temperature history in Antarctica is important for a better understanding of human‐induced climate changes, especially since the Industrial Revolution. We present here a surface temperature history spanning the last century at Styx Glacier, located on the eastern coast of northern Victoria Land, which is reconstructed using borehole logging data. Our results indicate that surface temperatures in the 20th century were 1.7 ± 0.4 °C higher than the long term averages over 1600–1900 Common Era, indicating regional warming over the eastern coast of northern Victoria Land. However, we found no evidence for significant warming across the northern Victoria Land since the mid‐20th century. A global reanalysis as well as the reconstruction of proxy records demonstrate that the climate in this region was more affected by changes in the Southern Hemisphere Annular Mode than in the Amundsen‐Bellingshausen Sea Low.
California Winter Precipitation Predictability: Insights From the Anomalous 2015–2016 and 2016–2017 Seasons
Authors: Singh Deepti , Ting Mingfang , Scaife Adam A. , Martin Nicola 
Published: September 2018

AbstractThe unexpected dry 2015–2016 El Niño winter and extremely wet 2016–2017 La Niña winter in California challenged current seasonal prediction systems. Using the Met Office GloSea5 forecast ensemble, we study the precipitation and circulation differences between these seasons and identify processes relevant to California precipitation predictions. The ensemble mean accurately predicts the midlatitude atmospheric circulation differences between these years, indicating that these differences were predictable responses to the strong oceanic forcing differences. The substantial California precipitation differences were poorly predicted with large uncertainty. Notable differences in high‐latitude circulation anomalies associated with internal variability distinguish the ensemble members that successfully simulate precipitation from those that do not. Specifically, accurate representation of the Arctic Oscillation phase differences improves the accuracy of simulated precipitation differences but these differences were not well predicted in the ensemble mean for these seasons. Improved representation of high‐latitude processes such as the Arctic Oscillation and polar‐midlatitude teleconnections could therefore improve California seasonal predictions.
Major Volatiles Evolved From Eolian Materials in Gale Crater
Authors: Stern Jennifer C. , Sutter Brad , Archer P. Douglas , Eigenbrode Jennifer L. , McAdam Amy C. , Franz Heather B. , Knudson Christine , Ming Douglas W. , Wong Gregory , Freissinet Caroline , Malespin Charles A. , Navarro‐Gonzalez Rafael , Szopa Cyril , Mahaffy Paul R. 
Published: September 2018

AbstractThe Sample Analysis at Mars on the Curiosity rover analyzed the major volatile content of four eolian samples at three locations in Gale crater. The Rocknest sample was taken from an inactive sand shadow with a significant component of dust‐sized grains, while Gobabeb and Ogunquit Beach samples were taken from different locations in the Bagnold Dune field and had dust‐free, fine sand sized grains. All eolian samples possessed more oxychlorine, carbon, and nitrate relative to sedimentary materials in Gale crater. Evolved CO2 above 450 °C was consistent with ~0.7 and ~0.4 wt. % carbonate in the Bagnold Dunes and Rocknest materials, respectively, with a regional source inside Gale crater. The fine‐grained phase of Rocknest was enriched in adsorbed water and perhaps in Fe sulfate and Fe nitrate/nitrite compared to coarser Bagnold materials and was estimated to contain up to ~0.1 wt. % of organic carbon.
Benefits of Seasonal Climate Prediction and Satellite Data for Forecasting U.S. Maize Yield
Authors: Peng Bin , Guan Kaiyu , Pan Ming , Li Yan 
Published: September 2018

AbstractSeasonal agricultural production forecasting is essential for agricultural supply chain and economic prediction. However, to what extent seasonal climate prediction and remote sensing observations can improve crop yield forecasting at regional scale remains unknown. Using a statistical seasonal forecasting framework for U.S. county‐level maize yield, we demonstrated that (1) incorporating satellite‐based enhanced vegetation index (EVI) significantly improved the yield forecasting performance, compared with other climate‐only models using monthly air temperature (T), precipitation (P), and vapor pressure deficit (VPD). (2) The bias‐corrected climate prediction from the Coupled Forecast System model version 2 (CFSv2) showed better yield forecasting performance than the historical climate ensemble. (3) Using the “T + P + VPD + EVI” model with climate prediction from bias‐corrected climate prediction from CFSv2 outperformed the yield forecast in the World Agricultural Supply and Demand Estimates reports released by the United States Department of Agriculture, with root‐mean‐square error of 4.37 bushels per acre (2.79% of multiyear averaged yield) by early August.
A Recent Reversal in the Poleward Shift of Western North Pacific Tropical Cyclones
Authors: Sun Y. , Li T. , Zhong Z. , Yi L. , Chen X. , Ha Y. , Zhu J. , Shen Y. , Xu Z. , Hu Y. 
Published: September 2018

AbstractRecent studies have revealed a global, poleward migration trend of tropical cyclones (TCs) in terms of annual‐averaged latitude of lifetime maximum intensity under the global warming. The TCs in the western North Pacific (WNP) make the largest contribution to this trend. One existing hypothesis is that there is a linkage between poleward migration of TCs and anthropogenic forcing. Here we introduce a new measurement, the lifetime‐averaged latitude weighted by TC destructive potential, to detect the meridional migration of the WNP TCs, which is more reliable and meaningful as it considers not only past data uncertainty but also public concerns. Our results show that the trend of WNP TC migration reversed during the recent warming slowing‐down period (after ~1999). Different from the existing hypothesis, it is the change of regional pattern of sea surface temperature that contributes greatly to the meridional migration of WNP TCs.
Revisiting Liquid Water Content Retrievals in Warm Stratified Clouds: The Modified Frisch
Authors: Küchler N. , Kneifel S. , Kollias P. , Löhnert U. 
Published: September 2018

AbstractAccurate observations of liquid water content (LWC) in warm stratiform clouds are important for quantifying their radiative and hydrological effects and for studying aerosol‐cloud interactions. Retrieving LWC from radar reflectivity under drizzling or nondrizzling conditions has been investigated for several decades by the cloud remote sensing community. However, no physically plausible framework exists to address the biases introduced by drizzle on existing retrieval techniques. We present the modified Frisch retrieval (ModFrisch), which combines radar and microwave radiometer measurements to retrieve LWC in both nondrizzling and drizzling conditions. It is shown, using a 1‐D steady state microphysical model and a radar simulator, that the uncertainty of ModFrisch is up to four times smaller than the uncertainty of similar retrievals under drizzling conditions, enabling LWC profiling with an accuracy of 20%. The performance of the ModFrisch technique is evaluated using 1 year of observations.
Ionospheric Response Observed by EISCAT During the 6–8 September 2017 Space Weather Event: Overview
Authors: Yamauchi M. , Sergienko T. , Enell C.‐F. , Schillings A. , Slapak R. , Johnsen M. G. , Tjulin A. , Nilsson H. 
Published: September 2018

AbstractWe present ionospheric plasma conditions observed by the EISCAT radars in Tromsø and on Svalbard, covering 68°–81° geomagnetic latitude, during 6–8 September 2017. This is a period when X2.2 and X9.3 X‐ray flares occurred, two interplanetary coronal mass ejections (ICMEs) arrived at the Earth accompanied by enhancements of MeV‐range energetic particle flux in both the solar wind (SEP event) and inner magnetosphere, and an AL < −2,000 substorm took place. (1) Both X flares caused enhancement of ionospheric electron density for about 10 min. The X9.3 flare also increased temperatures of both electrons and ions over 69°–75° geomagnetic latitude until the X‐ray flux decreased below the level of X‐class flares. However, the temperature was not enhanced after the previous X2.2 flare in the prenoon sector. (2) At around 75° geomagnetic latitude, the prenoon ion upflow flux slightly increased the day after the X9.3 flare, which is also after the first ICME and a SEP event, while no outstanding enhancement was found at the time of these X flares. (3) The upflow velocity sometimes decreased when the interplanetary magnetic field (IMF) turned southward. (4) Before the first ICME arrival after the SEP event under weak IMF with Bz ~0 nT, a substorm‐like expansion of the auroral arc signature took place without local geomagnetic signature near local midnight, while no notable change was observed after the ICME arrival. (5) AL reached <−2,000 nT only after the arrival of the second ICME with strongly southward IMF. Causality connections between the solar/solar wind event and the ionospheric responses remain unclear.
Lithosphere Destabilization by Melt Weakening and Crust‐Mantle Interactions: Implications for Generation of Granite‐Migmatite Belts
Authors: Kaislaniemi L. , van Hunen J. , Bouilhol Pierre 
Published: September 2018

AbstractOrogenic crustal anatexis is a still poorly understood process due to the complexity of the thermal and geodynamical interaction between mantle and crustal processes during and after continental collision. Here we present a novel conceptual model for the formation of granite‐migmatite belts: we propose that convective thinning of the lithosphere results in minor amounts of partial melts within the lowermost crust that trigger further instabilities. This will lead to positive feedback effects between melt weakening, mantle upwelling, and wholesale mantle lithosphere removal, causing a strong pulse of mantle and crustal melting. We test this model numerically, and results show that this process, taking between 20 and 50 Myr in total, can explain the temporal evolution of melting in granite‐migmatite zones and associated mantle‐derived mafic rocks and provides a heat source for crustal melting without the need for other processes, such as slab break‐off or increased radiogenic heating. Furthermore, the generation of a refractory residue after mantle and crustal melting is also shown to control the progress of the lithospheric mantle removal, providing another feedback mechanism between melting and lithospheric reequilibration.
Surface Faulting of the 30 October 2016 Mw 6.5 Central Italy Earthquake: Detailed Analysis of a Complex Coseismic Rupture
Authors: Villani F. , Pucci S. , Civico R. , De Martini P. M. , Cinti F. R. , Pantosti D. 
Published: September 2018

Key Points

We analyze the surface ruptures of the 30 October 2016 Mw 6.5 Norcia normal‐faulting earthquake in central Italy
The heterogeneity of surface slip, with peaks up to 2.10 m, is controlled by the coseismic rupture process at depth
The scaling properties and the complexity of surface slip reveal processes of fault segmentation and strain localization
A Comprehensive Framework to Evaluate Hydraulic and Water Quality Impacts of Pipe Breaks on Water Distribution Systems
Authors: Qi Zhexian , Zheng Feifei , Guo Danlu , Zhang Tuqiao , Shao Yu , Yu Tingchao , Zhang Kejia , Maier Holger R. 
Published: September 2018

AbstractPipe breaks have significant impacts on the hydraulic and water quality performance of water distribution systems (WDSs). Therefore, it is important to evaluate these impacts for developing effective strategies to ultimately minimize the consequences of these events. However, there has been surprisingly limited research focusing on impact evaluation for pipe breaks so far. To address this gap, this paper proposes a framework to comprehensively evaluate hydraulic and water quality impacts of pipe breaks on a WDS using six quantitative metrics. These metrics primarily focus on identifying (i) break outflow volume, (ii) water shortage, (iii) nodes with reduced service quality, (iv) pipes with affected pressures, (v) pipes with reversed flow directions, and (vi) pipes with significantly increased velocities, for each breaking event within a WDS. Statistical behaviors, spatial properties, and pipe rankings of metric results are analyzed to reveal the underlying characteristics of impacts induced by pipe breaks. We illustrate the proposed framework using three WDSs with different properties. Results show that impacts of pipe breaks not only vary with pipe diameters but are also significantly influenced by pipe locations, when the break occurs, and the specific metric considered. The proposed framework greatly enhances the fundamental understanding of the underlying properties of breaking impacts on the hydraulic and water quality of WDSs, as well as the ranking of pipes based on the consequences of breaks. Such understanding offers important guidance to develop effective pipe management, resource planning, and break restoration strategies to minimize the impacts of breaking events on WDSs.