bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of the Martian cold oxygen corona from the O I 130.4 nm by IUVS/MAVEN
Authors: Chaufray J. Y. , Deighan J. , Chaffin M. S. , Schneider N. M. , McClintock W. E. , Stewart A. I. F. , Jain S. K. , Crismani M. , Stiepen A. , Holsclaw G. M. , Clarke J. T. , Montmessin F. , Eparvier F. G. , Thiemann E. M. B. , Chamberlin P. C. , Jakosky B. M. 
Published: November 2015

AbstractFirst observations of the O I 130.4 nm resonant line performed by the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) are presented in this paper. This emission line is observed during the different orbit phases of MAVEN. The atomic oxygen density and the temperature at 200 km are retrieved from an automatic pipeline using a radiative transfer model for resonant scattering lines for a selection of coronal profiles. These selected profiles are representative of the coronal scans done during the first months of the mission (from November 2014 to January 2015). The derived oxygen density and the temperature near the exobase are in the predicted range by the current thermospheric models of Mars for moderate solar activity, and some diurnal variations are observed. However, the absolute calibration of the instrument significantly limits the accuracy of density and temperature results.
MAVEN IUVS observation of the hot oxygen corona at Mars
Authors: Deighan J. , Chaffin M. S. , Chaufray J.‐Y. , Stewart A. I. F. , Schneider N. M. , Jain S. K. , Stiepen A. , Crismani M. , McClintock W. E. , Clarke J. T. , Holsclaw G. M. , Montmessin F. , Eparvier F. G. , Thiemann E. M. B. , Chamberlin P. C. , Jakosky B. M. 
Published: November 2015

AbstractObservation of the hot oxygen corona at Mars has been an elusive measurement in planetary science. Characterizing this component of the planet's exosphere provides insight into the processes driving loss of oxygen at the current time, which informs understanding of the planet's climatic evolution. The Mars Atmosphere and Volatile EvolutioN (MAVEN) Imaging Ultraviolet Spectrograph (IUVS) instrument is now regularly collecting altitude profiles of the hot oxygen corona as part of its investigation of atmospheric escape from Mars. Observations obtained thus far have been examined and found to display the expected gross structure and variability with EUV forcing anticipated by theory. The quality and quantity of the data set provides valuable constraints for the coronal modeling community.
Time reverse imaging for far‐field tsunami forecasting: 2011 Tohoku earthquake case study
Authors: Hossen M. Jakir , Cummins Phil R. , Dettmer Jan , Baba Toshitaka 
Published: November 2015

AbstractThis paper describes a new method for forecasting far‐field tsunamis by combining aspects of least squares tsunami source inversion (LSQ) with time reverse imaging (TRI). This method has the same source representation as LSQ but uses TRI to estimate initial sea surface displacement. We apply this method to the 2011 Japan tsunami, and the results show that the method produces tsunami waveforms of excellent agreement with observed waveforms at both near‐ and far‐field stations not used in the source estimation. The spatial distribution of cumulative sea surface displacement agrees well with other models obtained in more sophisticated inversions, but resolve source kinematics are not well resolved. The method has potential for application in tsunami warning systems, as it is computationally efficient and can be used to estimate the initial source model by applying precomputed Green's functions in order to provide more accurate and realistic tsunami predictions.
Investigation of coseismic and postseismic processes using in situ measurements of seismic velocity variations in an underground mine
Authors: Olivier G. , Brenguier F. , Campillo M. , Roux P. , Shapiro N. M. , Lynch R. 
Published: November 2015

AbstractThe in situ mechanical response of a rock mass to a sudden dynamic and static stress change is still poorly known. To tackle this question, we conducted an experiment in an underground mine to examine (1) the influence of dynamic and static stress perturbations on seismic velocities, (2) elastic static stress changes, and (3) induced earthquake activity associated with the blast and removal of a portion of hard rock. We accurately (0.01%) measured seismic velocity variations with ambient seismic noise correlations, located aftershock activity, and performed elastic static stress modeling. Overall, we observe that the blast induced a sudden decrease in seismic velocities over the entire studied area, which we interpreted as the damage due to the passing of strong seismic waves. This sudden process is followed by a slow relaxation lasting up to 5 days, while seismic activity returns to its background level after 2 days. In some locations, after the short‐term effects of the blast have subsided, the seismic velocities converge to new baseline levels and permanent changes in seismic velocity become visible. After comparing the spatial pattern of permanent seismic velocity changes with elastic static stress modeling, we infer that the permanent seismic velocity changes are due to the change in the static volumetric stress induced by the removal of a solid portion of rock by the blast. To our knowledge, this is the first observation of noise‐based permanent seismic velocity changes associated with static stress changes.
Changes in the thermosphere and ionosphere of Mars from Viking to MAVEN
Authors: Withers Paul , Vogt Marissa , Mahaffy Paul , Benna Mehdi , Elrod Meredith , Jakosky Bruce 
Published: November 2015

AbstractWe compare Viking and Mars Atmosphere and Volatile EvolutioN mission (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) observations of the thermosphere and ionosphere of Mars in order to test predictions of large variations in conditions over the solar cycle and with season. Substantial differences exist between the Viking observations at solar minimum and near aphelion and the MAVEN NGIMS observations at moderate solar activity and near perihelion. Differences in the O/CO2 ratio, the O+ ionospheric peak, ion densities at high altitude, and neutral and ion scale heights can be attributed to differences in solar activity and season, but the relative importance of solar activity and season for these differences was not established. Current models do not explain the observed differences in the mixing ratios of N, NO, and O2. These results place new constraints on models of how the thermosphere and ionosphere of Mars vary over the solar cycle and with season.
The relative contribution of orbital forcing and greenhouse gases to the North American deglaciation
Authors: Gregoire Lauren J. , Valdes Paul J. , Payne Antony J. 
Published: November 2015

AbstractUnderstanding what drove Northern Hemisphere ice sheet melt during the last deglaciation (21–7 ka) can help constrain how sensitive contemporary ice sheets are to greenhouse gas (GHGs) changes. The roles of orbital forcing and GHGs in the deglaciation have previously been modeled but not yet quantified. Here for the first time we calculate the relative effect of these forcings on the North American deglaciation by driving a dynamical ice sheet model (GLIMMER‐CISM) with a set of unaccelerated transient deglacial simulations with a full primitive equation‐based ocean‐atmosphere general circulation model (FAMOUS). We find that by 9 ka, orbital forcing has caused 50% of the deglaciation, GHG 30%, and the interaction between the two 20%. Orbital forcing starts affecting the ice volume at 19 ka, 2000 years before CO2 starts increasing in our experiments, a delay which partly controls their relative effect.
Seasonal variability of eddy kinetic energy in a global high‐resolution ocean model
Authors: Rieck Jan K. , Böning Claus W. , Greatbatch Richard J. , Scheinert Markus 
Published: November 2015

AbstractA global ocean model with 1/12° horizontal resolution is used to assess the seasonal cycle of surface eddy kinetic energy (EKE). The model reproduces the salient features of the observed mean surface EKE, including amplitude and phase of its seasonal cycle in most parts of the ocean. In all subtropical gyres of the Pacific and Atlantic, EKE peaks in summer down to a depth of ∼350 m, below which the seasonal cycle is weak. Investigation of the possible driving mechanisms reveals the seasonal changes in the thermal interactions with the atmosphere to be the most likely cause of the summer maximum of EKE. The development of the seasonal thermocline in spring and summer is accompanied by stronger mesoscale variations in the horizontal temperature gradients near the surface which corresponds, by thermal wind balance, to an intensification of mesoscale velocity anomalies toward the surface.
Evidence for long‐lived subduction of an ancient tectonic plate beneath the southern Indian Ocean
Authors: Simmons N. A. , Myers S. C. , Johannesson G. , Matzel E. , Grand S. P. 
Published: November 2015

AbstractAncient subducted tectonic plates have been observed in past seismic images of the mantle beneath North America and Eurasia, and it is likely that other ancient slab structures have remained largely hidden, particularly in the seismic‐data‐limited regions beneath the vast oceans in the Southern Hemisphere. Here we present a new global tomographic image, which shows a slab‐like structure beneath the southern Indian Ocean with coherency from the upper mantle to the core‐mantle boundary region—a feature that has never been identified. We postulate that the structure is an ancient tectonic plate that sank into the mantle along an extensive intraoceanic subduction zone that migrated southwestward across the ancient Tethys Ocean in the Mesozoic Era. Slab material still trapped in the transition zone is positioned near the edge of East Gondwana at 140 Ma suggesting that subduction terminated near the margin of the ancient continent prior to breakup and subsequent dispersal of its subcontinents.
Vulnerability of water availability in India due to climate change: A bottom‐up probabilistic Budyko analysis
Authors: Singh Riddhi , Kumar Rohini 
Published: November 2015

AbstractQuantifying the dependence of future water availability on changing climate is critical for water resources planning and management in water stressed countries like India. However, this remains a challenge as long‐term streamflow data are scarce, and there are significant uncertainties regarding future climate change. We present a bottom‐up probabilistic Budyko framework that estimates the vulnerability of available water to changing climate using three hydroclimatic variables: long‐term precipitation, potential evapotranspiration, and actual evapotranspiration. We assimilate these variables within a probabilistic Budyko framework to derive estimates of water availability and associated uncertainty. We then explore a large range of possible future climates to identify critical climate thresholds and their spatial variation across India. Based on this exploratory analysis, we find that southern India is most susceptible to changing climate with less than 10% decrease in precipitation causing a 25% decrease in water availability.
Hydrogen isotope fractionation and redox‐controlled solution mechanisms in silicate‐COH melt + fluid systems
Authors: Mysen Bjorn 
Published: November 2015

AbstractThe behavior of volatiles in silicate‐COH melts and fluids and hydrogen isotope fractionation between melt and fluid were determined experimentally to advance our understanding of the role of volatiles in magmatic processes. Experiments were conducted in situ while the samples were at the desired temperature and pressure to 825°C and ~1.6 GPa and with variable redox conditions. Under oxidizing conditions, melt and fluid comprised CO2, CO3, HCO3, OH, H2O, and silicate components, whereas under reducing conditions, the species were CH4, H2, H2O, and silicate components. Temperature‐dependent hydrogen isotope exchange among structural entities within coexisting fluids and melts yields ΔH values near 14 and 24 kJ/mol and −5 and −1 kJ/mol under oxidizing and reducing conditions, respectively. This temperature (and probably pressure)‐dependent D/H fractionation is because of interaction between D and H and silicate and C‐bearing species in silicate‐saturated fluids and in COH fluid‐saturated melts. The temperature‐ and pressure‐dependent D/H fractionation factors suggest that partial melts in the presence of COH volatiles in the upper mantle can have δD values 100% or more lighter relative to coexisting silicate‐saturated fluid. This effect is greater under oxidizing than under reducing conditions. It is suggested that δD variations of upper mantle mid‐ocean ridge basalt (MORB) sources, inferred from the δD of MORB magmatic rocks, can be explained by variations in redox conditions during melting. Lower δD values of the MORB magma reflect more reducing conditions in the mantle source.
Reconstruction of a meteotsunami in Lake Erie on 27 May 2012: Roles of atmospheric conditions on hydrodynamic response in enclosed basins
Authors: Anderson Eric J. , Bechle Adam J. , Wu Chin H. , Schwab David J. , Mann Greg E. , Lombardy Kirk A. 
Published: November 2015

AbstractOn 27 May 2012, atmospheric conditions gave rise to two convective systems that generated a series of waves in the meteotsunami band on Lake Erie. The resulting waves swept three swimmers a 0.5 mi offshore, inundated a marina, and may have led to a capsized boat along the southern shoreline. Analysis of radial velocities from a nearby radar tower in combination with coastal meteorological observation indicates that the convective systems produced a series of outflow bands that were the likely atmospheric cause of the meteotsunami. In order to explain the processes that led to meteotsunami generation, we model the hydrodynamic response to three meteorological forcing scenarios: (i) the reconstructed atmospheric disturbance from radar analysis, (ii) simulated conditions from a high‐resolution weather model, and (iii) interpolated meteorological conditions from the NOAA Great Lakes Coastal Forecasting System. The results reveal that the convective systems generated a series of waves incident to the southern shore of the lake that reflected toward the northern shoreline and reflected again to the southern shore, resulting in spatial wave focusing and edge wave formation that combined to impact recreational users near Cleveland, OH. This study illustrates the effects of meteotsunami development in an enclosed basin, including wave reflection, focusing, and edge wave formation as well as temporal lags between the causative atmospheric conditions and arrival of dangerous wave conditions. As a result, the ability to detect these extreme storms and predict the hydrodynamic response is crucial to reducing risk and building resilient coastal communities.
CO2 sink/source characteristics in the tropical Indonesian seas
Authors: Kartadikaria A. R. , Watanabe A. , Nadaoka K. , Adi N. S. , Prayitno H. B. , Soemorumekso S. , Muchtar M. , Triyulianti I. , Setiawan A. , Suratno S. , Khasanah E. N. 
Published: November 2015

AbstractTwo distinct CO2 sink/source characteristics are found in the tropical Indonesian seas from the compilation of observed data for the period 1984–2013. The western region persistently emits CO2 to the atmosphere, whereas the eastern region is dynamic and acts either as a small source or sink of CO2 to the atmosphere, depending on sites. The segregation is proximal to the Makassar Strait, which is located over the continental shelf and is one of the main routes of the Indonesian Throughflow (ITF). Lower salinity and higher silicate were found in the western region, suggesting a terrestrial influence in this area. Temperature has a limited influence in controlling different CO2 sink/source characteristics in the west and east. However, an SST change of −2.0°C during La Niña events effectively reduces the pCO2 difference between the atmosphere and surface seawater by 50% compared to normal year conditions. During La Niña events, higher wind speeds double the CO2 flux from the ocean to the atmosphere compared to that of a normal year. In the continental shelf area where the CO2 sink area was found, data of over 29 years show that the seawater pCO2 increased by 0.6–3.8 μatm yr−1. Overall, the seawater pCO2 of the Indonesian seas is supersaturated relative to the atmosphere by 15.9 ± 8.6 μatm and thus acts as a source of CO2 to the atmosphere.
A comparative assessment of coastal mean dynamic topography in Norway by geodetic and ocean approaches
Authors: Ophaug Vegard , Breili Kristian , Gerlach Christian 
Published: November 2015

AbstractThe ocean's mean dynamic topography (MDT) is the surface representation of ocean circulation. It may be determined by the ocean approach, using numerical ocean circulation models, or by the geodetic approach, where MDT is the height of the mean sea surface (MSS), or mean sea level (MSL), above the geoid. Using new geoid models, geodetic MDT profiles based on tide gauges, dedicated coastal altimetry products, and conventional altimetry are compared with six ocean MDT estimates independent of geodetic data. Emphasis is put on the determination of high‐resolution geoid models, combining ESA's fifth release (R5) of GOCE satellite‐only global gravity models (GGMs) with a regional geoid model for Norway by a filtering technique. Differences between MDT profiles along the Norwegian coast together with Taylor diagrams confirm that geodetic and ocean MDTs agree on the ∼3–7 cm level at the tide gauges, and on the ∼5–11 cm level at the altimetry sites. Some geodetic MDTs correlate more with the best‐performing ocean MDT than do other ocean MDTs, suggesting a convergence of the methods. While the GOCE R5 geoids are shown to be more accurate over land, they do not necessarily show the best agreement over the ocean. Pointwise monomission altimetry products give results comparable with the multimission DTU13MSS grid on the ∼5 cm level. However, dedicated coastal altimetry products generally do not offer an improvement over conventional altimetry along the Norwegian coast.
Cenozoic extension in the Kenya Rift from low‐temperature thermochronology: Links to diachronous spatiotemporal evolution of rifting in East Africa
Authors: Torres Acosta Verónica , Bande Alejandro , Sobel Edward R. , Parra Mauricio , Schildgen Taylor F. , Stuart Finlay , Strecker Manfred R. 
Published: November 2015

AbstractThe cooling history of rift shoulders and the subsidence history of rift basins are cornerstones for reconstructing the morphotectonic evolution of extensional geodynamic provinces, assessing their role in paleoenvironmental changes and evaluating the resource potential of their basin fills. Our apatite fission track and zircon (U‐Th)/He data from the Samburu Hills and the Elgeyo Escarpment in the northern and central sectors of the Kenya Rift indicate a broadly consistent thermal evolution of both regions. Results of thermal modeling support a three‐phased thermal history since the early Paleocene. The first phase (~65–50 Ma) was characterized by rapid cooling of the rift shoulders and may be coeval with faulting and sedimentation in the Anza Rift basin, now located in the subsurface of the Turkana depression and areas to the east in northern Kenya. In the second phase, very slow cooling or slight reheating occurred between ~45 and 15 Ma as a result of either stable surface conditions, very slow exhumation, or subsidence. The third phase comprised renewed rapid cooling starting at ~15 Ma. This final cooling represents the most recent stage of rifting, which followed widespread flood‐phonolite emplacement and has shaped the present‐day landscape through rift shoulder uplift, faulting, basin filling, protracted volcanism, and erosion. When compared with thermochronologic and geologic data from other sectors of the East African Rift System, extension appears to be diachronous, spatially disparate, and partly overlapping, likely driven by interactions between mantle‐driven processes and crustal heterogeneities, rather than the previously suggested north–south migrating influence of a mantle plume.
Hydrological response to changing climate conditions: Spatial streamflow variability in the boreal region
Authors: Teutschbein C. , Grabs T. , Karlsen R. H. , Laudon H. , Bishop K. 
Published: November 2015

AbstractIn this paper we combined a multimodel ensemble based on 15 regional climate models with a multicatchment approach to explore the hydrologic sensitivity of 14 neighboring and rather similar catchments to changing climate conditions. Current (1982–2010) and future (2062–2090) streamflow was simulated with the HBV model. A diagnostic approach was used, which considered major behavioral catchment functions by using hydrologically relevant signatures related to overall water balance, flow duration curves and hydrograph attributes. Projected increases in temperature and precipitation resulted in increased total available streamflow, with lower spring and summer flows, but substantially higher winter streamflow. Furthermore, significant changes in flow durations with lower chances of both high and low flows can be expected in boreal Sweden in the future. This overall trend in projected streamflow pattern changes was comparable among the analyzed catchments but the magnitude of change differed considerably. This suggests that catchments belonging to the same region can show distinctly different degrees of hydrological responses to the same external climate change signal. We reason that differences in spatially distributed physical catchment properties within catchments are not only of great importance for current streamflow behavior, but also play a major role in the sensitivity of catchments to changing climate conditions.
Diastereoselective Synthesis of Macrocyclic Spiro and Dispiro‐1,4‐dithianes, ‐1,4‐oxathianes, and ‐1,4‐dithiepanes through Intramolecular Sulfonium Ylides
Authors: Muthusamy Sengodagounder , Selvaraj Karuppu , Suresh Eringathodi 
Published: November 2015

AbstractThe synthesis of functionalized C2‐symmetric as well as unsymmetrical macrocyclic spiro and dispiro‐1,4‐dithianes, ‐1,4‐oxathianes, and 1,4‐dithiepanes was achieved in a highly diastereoselective manner from the reactions of thiol‐protected cyclic and acyclic diazocarbonyl compounds in the presence of a rhodium(II) acetate dimer catalyst at room temperature. These macrocyclic compounds were obtained by the formation of 9‐ to 13‐membered intramolecular sulfonium ylides followed by a Stevens rearrangement.