bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relocation of long‐period (LP) seismic events reveals en echelon fractures in the upper edifice of Turrialba volcano, Costa Rica
Authors: Zecevic Megan , De Barros Louis , Eyre Thomas S. , Lokmer Ivan , Bean Christopher J. 
Published: September 2016

AbstractSwarms of long‐period (LP) events were recorded on Turrialba volcano, Costa Rica, during a seismic field experiment in 2009. Families of LP events were previously identified and located using a joint inversion for source location and mechanism; however, the spatial resolution of the obtained locations was not sufficient for imaging the structures on which they occur. Using a waveform similarity‐based location method, we take advantage of the joint location‐mechanism inversion by relocating events around the obtained familial location. The location method is successfully tested on a synthetic data set and is then applied to the Turrialba LP data set. The relocated events are jointly interpreted with their source mechanisms and reveal an en echelon structure within the upper edifice of the volcano. This can be interpreted as a response of a shearing band with high fluid pressure inducing tensile fractures at unconsolidated rock layer interfaces within the upper edifice of the volcano.
Slab segmentation controls the interplate slip motion in the SW Hellenic subduction: New insight from the 2008Mw 6.8 Methoni interplate earthquake
Authors: Sachpazi M. , Laigle M. , Charalampakis M. , Sakellariou D. , Flueh E. , Sokos E. , Daskalaki E. , Galvé A. , Petrou P. , Hirn A. 
Published: September 2016

AbstractWe present an integrated approach of the seismic structure and activity along the offshore SW Hellenic subduction from combined observations of marine and land seismic stations. Our imaging of the slab top topography from teleseismic receiver function analysis at ocean bottom seismometers supports a trenchward continuation of the along‐dip slab faults beneath the Peloponnesus. We further show that their morphostructural control accounts for the backstepping of the thrust contact of the Mediterranean Ridge accretionary wedge over the upper plate. Local seismic activity offshore SW Peloponnesus constrained by ocean bottom seismometer observations reveals a correlation with specific features of the forearc: the Matapan Troughs. We study theMw 6.8 14.02.2008 interplate earthquake offshore SW Peloponnesus and show that its nucleation, rupture zone, and aftershocks sequence are confined to one slab panel between two adjacent along‐dip faults and are thus controlled by not only the offshore slab top segmentation but also the upper plate sea‐bottom morphology.
Constraining central Neo‐Tethys Ocean reconstructions with mantle convection models
Authors: Nerlich Rainer , Colli Lorenzo , Ghelichkhan Siavash , Schuberth Bernhard , Bunge Hans‐Peter 
Published: September 2016

AbstractA striking feature of the Indian Ocean is a distinct geoid low south of India, pointing to a regionally anomalous mantle density structure. Equally prominent are rapid plate convergence rate variations between India and SE Asia, particularly in Late Cretaceous/Paleocene times. Both observations are linked to the central Neo‐Tethys Ocean subduction history, for which competing scenarios have been proposed. Here we evaluate three alternative reconstructions by assimilating their associated time‐dependent velocity fields in global high‐resolution geodynamic Earth models, allowing us to predict the resulting seismic mantle heterogeneity and geoid signal. Our analysis reveals that a geoid low similar to the one observed develops naturally when a long‐lived back‐arc basin south of Eurasia's paleomargin is assumed. A quantitative comparison to seismic tomography further supports this model. In contrast, reconstructions assuming a single northward dipping subduction zone along Eurasia's margin or models incorporating a temporary southward dipping intraoceanic subduction zone cannot sufficiently reproduce geoid and seismic observations.
On the atmospheric response experiment to a Blue Arctic Ocean
Authors: Nakamura Tetsu , Yamazaki Koji , Honda Meiji , Ukita Jinro , Jaiser Ralf , Handorf Dörthe , Dethloff Klaus 
Published: September 2016

AbstractWe demonstrated atmospheric responses to a reduction in Arctic sea ice via simulations in which Arctic sea ice decreased stepwise from the present‐day range to an ice‐free range. In all cases, the tropospheric response exhibited a negative Arctic Oscillation (AO)‐like pattern. An intensification of the climatological planetary‐scale wave due to the present‐day sea ice reduction on the Atlantic side of the Arctic Ocean induced stratospheric polar vortex weakening and the subsequent negative AO. Conversely, strong Arctic warming due to ice‐free conditions across the entire Arctic Ocean induced a weakening of the tropospheric westerlies corresponding to a negative AO without troposphere‐stratosphere coupling, for which the planetary‐scale wave response to a surface heat source extending to the Pacific side of the Arctic Ocean was responsible. Because the resultant negative AO‐like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification.
Early growth dynamical implications for the steerability of stratospheric solar radiation management via sulfur aerosol particles
Authors: Benduhn François , Schallock Jennifer , Lawrence Mark G. 
Published: September 2016

AbstractAerosol growth dynamics may have implications for the steerability of stratospheric solar radiation management via sulfur particles. This paper derives a set of critical initial growth conditions that are analyzed as a function of two key parameters: the initial concentration of the injected sulfuric acid and its dilution rate with the surrounding air. Based upon this analysis, early aerosol growth dynamical regimes may be defined and classified in terms of their likelihood to serve as candidates for the controlled generation of a radiatively effective aerosol. Our results indicate that the regime that fulfills all critical conditions would require that airplane turbines be used to provide sufficient turbulence. The regime's parameter space is narrow and related to steep gradients, thus pointing to potential fine tuning requirements. More research, development, and testing would be required to refine our findings and determine their global‐scale implications.
Evidence for shallow megathrust slip across the Unalaska seismic gap during the great 1957 Andreanof Islands earthquake, eastern Aleutian Islands, Alaska
Authors: Nicolsky D. J. , Freymueller J. T. , Witter R. C. , Suleimani E. N. , Koehler R. D. 
Published: September 2016

AbstractWe reassess the slip distribution of the 1957 Andreanof Islands earthquake in the eastern part of the aftershock zone where published slip models infer little or no slip. Eyewitness reports, tide gauge data, and geological evidence for 9–23 m tsunami runups imply seafloor deformation offshore Unalaska Island in 1957, in contrast with previous studies that labeled the area a seismic gap. Here we simulate tsunami dynamics for a suite of deformation models that vary in depth and amount of megathrust slip. Tsunami simulations show that a shallow (5–15 km deep) rupture with ~20 m of slip most closely reproduces the 1957 Dutch Harbor marigram and nearby >18 m runup at Sedanka Island marked by stranded drift logs. Slip models >20 km deep predict waves that arrive too soon. Our results imply that shallow slip on the megathrust in 1957 extended east into an area that presently creeps.
SMAP observes flooding from land to sea: The Texas event of 2015
Authors: Fournier S. , Reager J. T. , Lee T. , Vazquez‐Cuervo J. , David C. H. , Gierach M. M. 
Published: September 2016

AbstractFloods can have damaging impacts on both land and sea, yet studies of flooding events tend to focus on only one side of the land/sea continuum. Here we present the first two‐sided analysis, focusing on the May 2015 severe flooding in Texas. Our investigation benefits from simultaneous measurements of land surface soil moisture and sea surface salinity from NASA's recent Soil Moisture Active Passive (SMAP) mission as well as ancillary data. We report the comprehensive chronology of the flooding: above average rainfall preceding the flood caused soils to saturate; record rainfall then generated record river discharge; and subsequently, an unusual freshwater plume associated with anomalous ocean currents formed in the north central Gulf of Mexico. Together with the Mississippi River plume, a rare “horseshoe” pattern was created that may have significant biogeochemical implications. Such integrated land/sea analysis of flood evolution can improve impact assessments of future extreme flooding events.
Bursty bulk flows at different magnetospheric activity levels: Dependence on IMF conditions
Authors: Zhang L. Q. , Baumjohann W. , Wang C. , Dai L. , Tang B. B 
Published: September 2016

AbstractBased on concurrent observations of the ACE and Geotail satellites from 1998 to 2005, we statistically analyzed and compared the earthward bursty bulk flows (BBFs) with local positive Bz under different interplanetary magnetic field (IMF) conditions. Four different magnetospheric activity levels (MALs), including quiet times and substorm growth/expansion/recovery phases, are considered. The properties of the BBFs, including their ion temperature (T), Vx component, x component of the energy flux density (Qx), and the solar wind dawn‐dusk electric field Ey (observed at ~1 AU), are analyzed. Main observations include the following: (1) BBF tends to have less penetration distance for northward IMF (NW‐IMF) than for southward IMF (SW‐IMF). Inward of 15 RE the BBFs for SW‐IMF are dominant. Few BBFs for NW‐IMF occur within 15 RE. (2) The occurrence probabilities of the BBFs at each MAL depend highly on the orientations of the IMF. During quiet times, the BBFs for NW‐IMF are dominant. Reversely, during the growth and expansion phases of a substorm, the BBFs for SW‐IMF are dominant. (3) The strengths of the BBF have significant evolution with substorm development. For SW‐IMF condition, the strengths of the BBFs are the lowest for quiet times. The strength of the BBFs tends to increase during the growth phase and reaches to the strongest value during the expansion phase, then, decays during the recovery phase. For NW‐IMF condition, the strengths of the BBFs evolve with the substorm development in a similar way as for SW‐IMF condition. (4) For SW‐IMF, the solar wind Ey evolves with the substorm development in a similar way to the strength of the BBFs. However, no clear evolution is found for NW‐IMF. (5) The strengths of the BBF Qx and solar wind Ey are closely related. Both tend to be stronger for growth phase than for quite time, reach the strongest for expansion phase, then decay for recovery phase. It appears that to trigger a substorm, the strength of the BBFs should achieve energy thresholds with values different for NW‐IMF and SW‐IMF.
Variations of ionospheric plasma at different altitudes before the 2005 Sumatra Indonesia Ms 7.2 earthquake
Authors: Liu Jing , Zhang Xuemin , Novikov Victor , Shen Xuhui 
Published: September 2016

AbstractIn recent years, many researchers pay more attention to abnormities before earthquake, and in this study, seismo‐ionospheric synchronous disturbances at different altitudes by GPS and satellite observations were first studied around one Sumatra Indonesia Ms 7.2 earthquake that occurred on 5 July 2005. By using the same temporal and spatial methods, data of GPS‐total electron content (TEC) from Jet Propulsion Laboratory, electron density (Ne) from Detection of Electro‐Magnetic Emissions Transmitted from Earthquake Regions, and ion density (Ni) from Defense Meteorological Satellite Program were deeply analyzed. The ionospheric plasma disturbances in GPS‐TEC and increasement of Ne at 710 km were found on 4 July, and plasma density at the three altitudes has all increased on 7 July after the earthquake. All the disturbances were not just above the epicenter. TEC perturbations have happened at the east of the epicenter for the two days, and electron density enhancement at 710 km has moved to west of the TEC perturbations at the same time on 4 July, which may be caused by E × B drift. The moving direction of upgoing plasma was simulated using SAMI2 model. The results have shown that the plasma will move to higher altitude along the geomagnetic force line, which could exactly account for the plasma density enhancement in the northern direction of the geomagnetic south latitude earthquake.
Remote forcing of subsurface currents and temperatures near the northern limit of the California Current System
Authors: Engida Zelalem , Monahan Adam , Ianson Debby , Thomson Richard E. 
Published: September 2016

AbstractLocal and remote wind forcing of upwelling along continental shelves of coastal upwelling regions play key roles in driving biogeochemical fluxes, including vertical net fluxes of carbon and nutrients. These fluxes are responsible for high primary productivity, which in turn supports a lucrative fishery in these regions. However, the relative contributions of local versus remote wind forcing are not well quantified or understood. We present results of coherence analyses between currents at a single mooring site (48.5°N, 126°W) in the northern portion of the California Current System (CalCS) from 1989 to 2008 and coincident time series of North America Regional Reanalysis (NARR) 10 m wind stress within the CalCS (36–54°N, 120–132°W). The two‐decade‐long current records from the three shallowest depths (35, 100, and 175 m) show a remote response to winds from south as far as 36°N. In contrast, only temperatures at the deepest depth (400 m) show strong coherences with remote winds. Weaker local wind influence is observed in both the currents and 400 m temperatures but is mostly due to the large spatial coherence within the wind field itself. Lack of coherence between distal winds and the 400 m currents suggests that the temperature variations at that depth are driven by vertical motion resulting from poleward travelling coastal trapped waves (CTWs). Understanding the effects of remote forcing in coastal upwelling regions is necessary for determining the occurrence and timing of extreme conditions in coastal oceans, and their subsequent impact on marine ecosystems.
Improving the simulation of landfast ice by combining tensile strength and a parameterization for grounded ridges
Authors: Lemieux Jean‐François , Dupont Frédéric , Blain Philippe , Roy François , Smith Gregory C. , Flato Gregory M. 
Published: September 2016

AbstractIn some coastal regions of the Arctic Ocean, grounded ice ridges contribute to stabilizing and maintaining a landfast ice cover. Recently, a grounding scheme representing this effect on sea ice dynamics was introduced and tested in a viscous‐plastic sea ice model. This grounding scheme, based on a basal stress parameterization, improves the simulation of landfast ice in many regions such as in the East Siberian Sea, the Laptev Sea, and along the coast of Alaska. Nevertheless, in some regions like the Kara Sea, the area of landfast ice is systematically underestimated. This indicates that another mechanism such as ice arching is at play for maintaining the ice cover fast. To address this problem, the combination of the basal stress parameterization and tensile strength is investigated using a 0.25° Pan‐Arctic CICE‐NEMO configuration. Both uniaxial and isotropic tensile strengths notably improve the simulation of landfast ice in the Kara Sea but also in the Laptev Sea. However, the simulated landfast ice season for the Kara Sea is too short compared to observations. This is especially obvious for the onset of the landfast ice season which systematically occurs later in the model and with a slower build up. This suggests that improvements to the sea ice thermodynamics could reduce these discrepancies with the data.
A Lagrangian analysis of cold cloud clusters and their life cycles with satellite observations
Authors: Esmaili Rebekah Bradley , Tian Yudong , Vila Daniel Alejandro , Kim Kyu‐Myong 
Published: September 2016

AbstractCloud movement and evolution signify the complex water and energy transport in the atmosphere‐ocean‐land system. Detecting, clustering, and tracking clouds as semicoherent clusters enable study of their evolution which can complement climate model simulations and enhance satellite retrieval algorithms, where there are gaps between overpasses. Using a cluster tracking algorithm, in this study we examine the trajectories, size, and brightness temperature of millions of cloud clusters over their lifespan, from infrared satellite observations at 30 min, 4 km resolution, for a period of 11 years. We found that the majority of cold clouds were both small and short lived and that their frequency and location are influenced by El Niño. Also, this large sample of individually tracked clouds shows their horizontal size and temperature evolution. Long‐lived clusters tended to achieve their temperature and size maturity milestones at different times, while these stages often occurred simultaneously in short‐lived clusters. On average, clusters with this lag also exhibited a greater rainfall contribution than those where minimum temperature and maximum size stages occurred simultaneously. Furthermore, by examining the diurnal cycle of cluster development over Africa and the Indian subcontinent, we observed differences in the local timing of the maximum occurrence at different life cycle stages. Over land there was a strong diurnal peak in the afternoon, while over the ocean there was a semidiurnal peak composed of longer‐lived clusters in the early morning hours and shorter‐lived clusters in the afternoon. Building on regional specific work, this study provides a global long‐term survey of object‐based cloud characteristics.
Low sediment‐water gas exchange in a small boreal lake
Authors: Kokic Jovana , Sahlée Erik , Brand Andreas , Sobek Sebastian 
Published: September 2016

AbstractBoreal lake sediments are carbon sources by producing CO2. CO2 flux from sediments is partly controlled by turbulence in the water column, which is not given the same attention as CO2 production rates in current estimates of CO2 fluxes from sediments. We quantified the in situ CO2 flux across the sediment‐water interface in a small (0.07 km2) lake in Sweden by measuring the in situ O2 flux with the Eddy Correlation (EC) method and using the apparent respiratory quotient (CO2 production:O2 consumption) derived from sediment incubations. We demonstrate that median CO2 flux estimated by EC was ~70% smaller than estimated by sediment incubations with artificial water mixing (1.0 × 10−2 and 3.6 × 10−2 µmol C m−2 s−1, respectively). Additionally, we show that inducing artificial mixing of supernatant water in the incubation experiment has a positive effect on observed fluxes, enhancing CO2 flux by ~30% compared to not mixing supernatant water. We suggest that the difference between the methods is due to the strong artificial water mixing in sediment incubations compared to the turbulent mixing in this small lake. Additionally, low O2 supply to sediment aerobic heterotrophic microbes during extended periods of low water currents can inhibit respiration and thus CO2 production. These findings suggest that the sediment contribution to total lake CO2 emission might currently be overestimated for small boreal lakes. Care should be taken when upscaling sediment CO2 flux derived from incubation experiments to entire basins of small lakes, as incubation experiments are unlikely to accurately mimic in situ bottom water currents and gas exchange.
Historical trends of forest fires and carbon emissions in China from 1988 to 2012
Authors: Zhang Yujin , Qin Dahe , Yuan Wenping , Jia Bingrui 
Published: September 2016

AbstractA larger amount of carbon is stored in forest ecosystems than in the entire atmosphere. Thus, relatively small changes in forest carbon stocks can significantly impact net carbon exchange between the biosphere and atmosphere. Changes in forest stocks can result from various disturbances, such as insect pests, windstorms, flooding, and especially forest fires. Globally, the impact of forest fires has been enhanced due to ongoing warming of the climate. The current study reported an evaluation of carbon emissions from historical forest fires in China during 1988–2012 with observational data collected from national agriculture statistics. Historical fire trends and fire‐induced carbon emissions were described over space and time at both national and regional levels. The results indicated that no significant increases in fire occurrence and carbon emissions were observed during the study period at the national level. However, at the regional level, there was a significant increasing trend in fire occurrence, and drought severity was a major driver of fire activity. Most carbon emissions were from north and northeast China, and these emissions contributed significantly to total carbon emissions. The results also showed that annual fire‐induced emissions ranged from 0.04 Tg C to 7.22 Tg C, with an average of 1.03 Tg C. Large interannual and spatial variabilities of carbon emissions were also indicated, and these were attributed to spatial and temporal variations in fire regimes. The results improve understanding of fire characteristics and provide significant information for reducing model‐related uncertainty of fire‐induced carbon emissions.
Chitosan‐finished Antheraea mylitta silk fibroin nonwoven composite films for wound dressing
Authors: Srivastava Chandra Mohan , Purwar Roli 
Published: September 2016

ABSTRACTIn this study, we aimed to produce nonwoven wound‐dressing films made of Antheraea mylitta (tasar) silk fibroin by a solution‐casting method. These nonwoven films were finished with chitosan solutions of different concentrations ranging from 0.75 to 2% w/v with a pad–dry method to fabricate nonwoven composite films. Chitosan‐finished tasar fibroin nonwoven composite films (CMTFFs) showed higher mechanical and dynamic mechanical properties as compared to nonwoven tasar fibroin. The physical, structural, and thermal properties of the films were investigated. The hemocompatibility, cytocompatibility, and biodegradation tests showed that the CMTFF was a promising material for use as a wound dressing. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44341.
Pop‐it beads to introduce catalysis of reaction rate and substrate depletion effects
Authors: Gehret Austin U. 
Published: September 2016

AbstractA kinesthetic classroom activity was designed to help students understand enzyme activity and catalysis of reaction rate. Students served the role of enzymes by manipulating Pop‐It Beads as the catalytic event. This activity illuminates the relationship between reaction rate and reaction progress by allowing students to experience first‐hand the effect of substrate depletion on catalyzed reaction rate. Preliminary findings based on survey results and exam performance suggest the activity could prove beneficial to students in the targeted learning outcomes. Unique to previous kinesthetic approaches that model Michaelis‐Menten kinetics, this activity models the effects of substrate depletion on catalyzed reaction rate. Therefore, it could prove beneficial for conveying the reasoning behind the initial rate simplification used in Michaelis‐Menten kinetics. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(2):179–183, 2017.