bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Variations of Slip and Creep Rates Along the Southern and Central Dead Sea Fault and the Carmel–Gilboa Fault System
Authors: Hamiel Yariv , Piatibratova Oksana
Published: September 2021

Crustal deformation and seismic activity in the Levant is mainly related to the interplate Dead Sea Fault (DSF) and the intraplate Carmel–Gilboa Fault System (CGFS). In this study, we analyze the interseismic deformation along these fault systems using 23 years of Global Positioning System (GPS) measurements obtained from 209 campaign and 60 continuous stations. This GPS data set is the longest record and the densest data set for the DSF, the CGFS, and the Levant region. We use this data set to investigate the spatial variations of slip and creep rates along the southern and central sections of the DSF and the CGFS. Our inversion model results indicate that part of the tectonic motion is transferred from the DSF to the CGFS. We find that the left‐lateral strike‐slip motion along the DSF decreases in a rate of 0.9 ± 0.4 mm/year, from 4.8 ± 0.3 mm/year south to the intersection with the CGFS to 3.9 ± 0.4 mm/year north to this intersection. Along the CGFS, the left‐lateral strike‐slip motion ranges between ∼0.3 and 0.5 mm/year and the extension rate between ∼0.6 and 0.7 mm/year, indicating a total slip rate vector of 0.8 ± 0.4 mm/year in the DSF direction, in agreement with the reduction of slip rate along the DSF near the intersection with the CGFS. Shallow creep is found along the southern and central sections of the Dead Sea basin and the northern Jordan Valley section of the DSF, with creep rates of 3.4 ± 0.4 and 2.3 ± 0.4 mm/year, respectively. These creeping sections were identified as areas with thick Halite layers at the shallow subsurface. We suggest that shallow creep behavior along the DSF is govern by the presence and mechanical properties of the Halite, which probably allows plastic deformation and the transition to velocity strengthening at the shallow subsurface and promotes creep.
Spatio‐Temporal Analysis of Hypoxia in the Central Basin of Lake Erie of North America
Authors: Xu Wenzhao , Collingsworth Paris D. , Kraus Richard , Minsker Barbara
Published: September 2021

We develop a spatio‐temporal geostatistical interpolation framework to estimate hypoxia extent (dissolved oxygen [DO] concentrations below 2 mg/L) with data from a network of DO loggers. The framework uses empirical orthogonal functions and Bayesian kriging to identify the spatially varying temporal pattern and estimate the distribution of hypoxia, including estimation uncertainty. A prototype web application is also developed in R. The framework is applied to analyze spatio‐temporal dynamics of DO in the central basin of Lake Erie in North America using data sampled from a logger network placed on the lake bottom during the summers of 2014, 2015, and 2016. Cross‐validation results demonstrate that the framework is capable of capturing the dynamic nature of bottom hypoxia over offshore areas, but nearshore areas have poor interpolation performance due to the impacts of complex physical processes such as seiche events. The findings showed that in the central basin, hypoxia started to emerge in early August of 2014, while in 2015 and 2016 hypoxia began in July. The peak hypoxia extent occurred in late September 2014, mid‐August 2015, and early September 2016. The prediction error of the overall spatial extent of hypoxia was as large as 25% of the interpolation area based on current logger deployment. Based on the cross‐validation and interpolation error, we suggest placing more loggers in nearshore areas to reduce prediction error near the margins of the hypoxic zone.
Global 3‐D Electrical Conductivity Model of the World Ocean and Marine Sediments
Authors: Grayver Alexander V.
Published: September 2021

This study presents global 3‐D electrical conductivity models of the world ocean and marine sediments. Electrical conductivity of the ocean was calculated by invoking the Equation of State of Seawater (TEOS‐10) with temperature and salinity data retrieved from the World Ocean Atlas and a series of high‐resolution regional ocean climatology data sets. The resolution of the ocean conductivity atlas varies between 0. and 0. globally. The conductivity of marine sediments was estimated by using compaction and thermal gradient models constrained by real observations on a 5‐arc‐minute global marine sediment thickness grid. I present numerical simulations of electromagnetic (EM) induction responses that demonstrate a significant effect of 3‐D electrical conductivity of the ocean and marine sediments on EM responses for a broad range of frequencies. I show that both marine and land‐based surveys designed for subsurface conductivity imaging or Space Weather modeling will benefit from inclusion of more realistic conductivity models of the ocean and seabed sediments.
Charge Exchange Ion Losses in Saturn’s Magnetosphere
Authors: Sontag A. , Clark G. , Kollmann P.
Published: September 2021

While various source and loss processes have been proposed for ions in Saturn’s magnetosphere, it is not yet well understood what role they play in different regions. In this study, we use a physical model of charge exchange to predict how proton and water group ion intensity profiles evolve over time and compare the results to MIMI/CHEMS measurements collected during the Cassini mission. First, we divide the CHEMS data into inbound and outbound half‐orbit segments, and create intensity profiles for 3–220 keV H+ and W+ ions between 5 and 15 Saturn radii, then using the inbound half‐orbits as initial conditions, we find qualitative similarities between measured and predicted outbound intensity profiles. This result is important because it provides strong evidence that charge exchange is the dominant loss process for these species in this region. The observed rate of charge exchange also presents information on the density of Saturn’s neutral torus. We suggest that data‐model discrepancies in the water group ions may be an indication of a significant presence of ions with the water group mass that are multiply charged.
Association of Auroral Streamers and Bursty Bulk Flows During Different States of the Magnetotail: A Case Study
Authors: Ferdousi Banafsheh , Raeder Joachim , Zesta Eftyhia , Cramer William , Murphy Kyle
Published: September 2021

In‐situ measurements in the magnetotail are sparse and limited to single points. On the other hand, there is a broad range of observations, including magnetometers, aurora imagers, and radars, in the ionosphere. Since the nightside ionosphere resembles the magnetotail plasma sheet dynamics projection, it can be used to monitor the tail's dynamics. A proper interpretation of the ionosphere and ground observations necessitates understanding the coupling processes between the ionosphere and the magnetosphere. Here, we use the global magnetohydrodynamic simulation model, OpenGGCM‐CTIM‐RCM, to investigate these coupling processes during periods when the magnetic flux is transported through the tail via narrow fast flow channels, typically called bursty bulk flows (BBFs). We consider three relevant states of the magnetotail: immediately before the substorm's onset, during the expansion of the substorm, and during a steady magnetic convection (SMC) event. The number of flow channels increases, and they penetrate closer to the Earth during SMC. The IMF direction influences fast flows' location but not their orientation in the plasma sheet during this event. However, the dimension of fast flows and streamers do not depend on the IMF conditions and state of the magnetosphere.
Intercalibration of the Plasma Density Measurements in Earth's Topside Ionosphere
Authors: Smirnov Artem , Shprits Yuri , Zhelavskaya Irina , Lühr Hermann , Xiong Chao , Goss Andreas , Prol Fabricio S. , Schmidt Michael , Hoque Mainul , Pedatella Nicholas , Szabó‐Roberts Mátyás
Published: September 2021

Over the last 20 years, a large number of instruments have provided plasma density measurements in Earth's topside ionosphere. To utilize all of the collected observations for empirical modeling, it is necessary to ensure that they do not exhibit systematic differences and are adjusted to the same reference frame. In this study, we compare satellite plasma density observations from Gravity Recovery and Climate Experiment (GRACE), Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), CHAllenging Minisatellite Payload (CHAMP), Swarm, and Communications/Navigation Outage Forecasting System (C/NOFS) missions. Electron densities retrieved from GRACE K‐Band Ranging (KBR) system, previously shown to be in excellent agreement with incoherent scatter radar (ISR) measurements, are used as a reference. We find that COSMIC radio occultation (RO) densities are highly consistent with GRACE‐KBR observations showing a mean relative difference of <, and therefore no calibration factors between them are necessary. We utilize the outstanding three‐dimensional coverage of the topside ionosphere by the COSMIC mission to perform conjunction analysis with in situ density observations from CHAMP, C/NOFS, and Swarm missions. CHAMP measurements are lower than COSMIC by ∼. Swarm densities are generally lower at daytime and higher at nighttime compared to COSMIC. C/NOFS ion densities agree well with COSMIC, with a relative bias of ∼. The resulting cross‐calibration factors, derived from the probability distribution functions, help to eliminate the systematic leveling differences between the data sets, and allow using these data jointly in a large number of ionospheric applications.
The Signature of Geomagnetic Field External Drivers in Virtual Observatory 30‐day Means Derived From Swarm Data
Authors: Saturnino D. , Pais M. A. , Domingos J.
Published: September 2021

The separation of contributions from different sources in the magnetic field signal measured at satellite altitude is an open challenge. An approach to this problem, using Principal Component Analysis, is here applied to geomagnetic external field series at Virtual Observatories (VOs). These series are computed from an enlarged data set of Swarm data covering all local times and all geomagnetic activity levels between January 2014 and December 2019. For each 30‐day time window, the Equivalent Source Dipole technique is used to reduce all measurements inside a cylinder to one single “observation” at its axis and 500 km altitude. Our results reveal a first principal mode with dipolar geometry and time variation following very closely the RC‐index of geomagnetic activity. They display a resolved second principal mode with annual periodicity and of approximately zonal quadrupolar radial pattern, reminiscent of results in a previous study using VO series from a filtered satellite data set and with lower time resolution. We resort to the recent comprehensive model CM6 to identify a possible source for this second mode. We propose that the dipolar mode is the expression of the magnetospheric ring current dynamics, at 30‐day time resolution, and the quadrupolar mode is the expression of the annual asymmetry between local summer and winter Sq current vortices. Two fainter modes could be related to the equinoctial amplification of Sq vortices and the ionospheric dynamo modulation by nonmigrating tides. We show that a more uniform local time sampling could contribute to better resolve ionospheric structures.
Solar Wind Control of Magnetosheath Jet Formation and Propagation to the Magnetopause
Authors: LaMoury Adrian T. , Hietala Heli , Plaschke Ferdinand , Vuorinen Laura , Eastwood Jonathan P.
Published: September 2021

Magnetosheath jets are localized high‐dynamic pressure pulses originating at Earth's bow shock and propagating earthward through the magnetosheath. Jets can influence magnetospheric dynamics upon impacting the magnetopause; however, many jets dissipate before reaching it. In this study we present a database of 13,096 jets observed by the Time History of Events and Macroscale Interactions during Substorms spacecraft from 2008 to 2018, spanning a solar cycle. Each jet is associated with upstream solar wind conditions from OMNI. We statistically examine how solar wind conditions control the likelihood of jets forming at the shock, and the conditions favorable for jets to propagate through the magnetosheath and reach the magnetopause. We see that, for each solar wind quantity, these two effects are separate, but when combined, we find that jets are over 17 times more likely to reach and potentially impact the magnetopause when the interplanetary magnetic field (IMF) orientation is at a low cone angle, and approximately 8 times more likely during high speed solar wind. Low IMF magnitude, high Alfvén Mach number, and low density approximately double the number of jets at the magnetopause, while and dynamic pressure display no net effect. Due to the strong dependence on wind speed, we infer that jet impact rates may be solar cycle dependent as well as vary during solar wind transients. This is an important step towards forecasting the magnetospheric effects of magnetosheath jets, as it allows for predictions of jet impact rates based on measurements of the upstream solar wind.
Drop of Solar Wind at the End of the 20th Century
Authors: Yermolaev Yuri I. , Lodkina Irina G. , Khokhlachev Alexander A. , Yermolaev Michael Yu. , Riazantseva Maria O. , Rakhmanova Liudmila S. , Borodkova Natalia L. , Sapunova Olga V. , Moskaleva Anastasiia V.
Published: September 2021

Variations in the solar wind (SW) parameters with scales of several years are an important characteristic of solar activity and the basis for a long‐term space weather forecast. We examine the behavior of interplanetary parameters over 21–24 solar cycles (SCs) on the basis of the OMNI database (https://spdf.gsfc.nasa.gov/pub/data/omni). Since changes in the parameters can be associated with both changes in the number of different large‐scale types of SW and with variations in the values of these parameters at different phases of the solar cycle and during the transition from one cycle to another, we select the entire study period in accordance with the Catalog of large‐scale SW types for 1976–2019 (see the site http://www.iki.rssi.ru/pub/omni, [Yermolaev, Nikolaeva, et al., 2009, https://doi.org/10.1134/s0010952509020014], which covers the period from 21 to 24 SCs) and in accordance with the phases of the cycles, and average the parameters at selected intervals. In addition to a sharp drop in the number of interplanetary coronal mass ejections and associated sheath types, there is a noticeable drop in the value (by 20%–40%) of plasma parameters and magnetic field in different types of solar wind at the end of the 20th century and a continuation of the fall or persistence at a low level in the 23–24 cycles. Such a drop in the solar wind is apparently associated with a decrease in solar activity and manifests itself in a noticeable decrease in space weather factors.
Small‐Scale Magnetic Structures: Cluster Observations
Authors: Walker Simon N. , Balikhin Michael A. , Gedalin Michael , Canu Patrick , Yearby Keith H.
Published: September 2021

Within the inner magnetosphere, the occurrence of plasma waves and/or magnetic field structures plays an important role in the dynamics of the particle populations, accelerating some particles to higher energies while scattering others. The 2013 Cluster Inner Magnetosphere Campaign was designed to investigate this process based on observations made at small separation scales. In addition, it provides an ideal opportunity for the study of small‐scale structures. This paper presents observations of previously unreported small‐scale magnetic field structures and investigates their characteristics and spatial properties. These structures, seen in the STAFF‐SC data set, are characterized by a rotation in the field direction and are observed to have spatial sizes of a few tens of kilometers, with a central core region around 10 km and are probably filamentary current structures. Using a variance analysis, it was determined that the maximum variance direction was close to being perpendicular to the external magnetic field. Based on the size of the central core region the current density is of the order of 10–40 . While they may affect the profile of these structures, data calibration effects were ruled out as their origin.
Magnitude and Interevent Time Statistics of Strombolian Activity of Villarrica Volcano and Inference Regarding the Flow Regime
Authors: Lehr Johanna , Rabbel Wolfgang
Published: September 2021

The different flow regimes of two‐phase gas‐in‐liquid flow—as it occurs in the shallow conduit of basaltic volcanoes—are characterized by distinct frequency‐size distributions of the liquid and gaseous slugs. Assuming that the ascent of gaseous bubbles is indicated by seismic events, we explore the possibility of inferring the flow regime from the frequency distributions of magnitudes and interevent times. Our data set consists of 20,000 volcanic seismic events recorded in early March 2012 at Villarrica Volcano (Chile), which are commonly attributed to Strombolian activity. One crucial factor is the completeness of the catalog in terms of detectable amplitudes, which we assess using a stochastic simulation of the network output based on statistical properties of the ambient seismicity. Magnitudes, at which we consider the catalog complete, show an exponential occurrence. Yet, the simulation approach indicates that low magnitude events occur indeed more sparsely than expected for an exponential distribution, and that the magnitude distribution does not obey the Gutenberg‐Richter law. Interevent times are log‐normally distributed, which implies a preferred recurrence interval. The distributions are consistent with a slug flow regime. They correlate weakly with the preceding magnitude, suggesting that slugs coalesce while ascending.
Seismoelectric and Electroseismic Modeling in Stratified Porous Media With a Shallow or Ground Surface Source
Authors: Zheng Xu‐Zhen , Ren Hengxin , Butler Karl E. , Zhang Haiming , Sun Yao‐Chong , Zhang Wei , Huang Qinghua , Chen Xiaofei
Published: September 2021

For a shallow or ground surface source and receiver at the same level or close depth, it is very difficult or computationally inefficient to simulate seismoelectric or electroseismic wave‐fields in stratified porous media by current reflectivity methods, such as the Luco‐Apsel‐Chen generalized reflection and transmission method (LAC GRTM). In this work, the peak‐trough averaging method which has been proved effective and efficient in dealing with this kind of computational problem is adopted to update the seismoelectric and electroseismic modeling algorithm based on LAC GRTM. After thoroughly verifying the accuracy and computational efficiency of the updated algorithm, we utilize it to numerically investigate both the electroseismic and seismoelectric couplings. Snapshots of electroseismic wave‐fields indicate evanescent electroseismic conversion, a reverse process of evanescent seismoelectric conversion, dominates at relatively larger ratios of seismic wavelength to interface depth, whereas the interfacial radiation electroseismic conversion is more prominent for the opposite situation. Our seismoelectric modeling results demonstrate that electric signals can arrive at the ground surface a few milliseconds earlier than their causative seismic signals due to evanescent seismoelectric conversion. This is the first modeling result considering source‐receiver geometries on the surface capable of explaining similar phenomena reported in geophysical field observations of seismically induced electrokinetic effects over a long history. The updated algorithm offers an accurate and efficient tool for forward modeling and will benefit interpretations of field observations as well as future inversion studies.
Analyzing Explosive Volcanic Deposits From Satellite‐Based Radar Backscatter, Volcán de Fuego, 2018
Authors: Dualeh E. W. , Ebmeier S. K. , Wright T. J. , Albino F. , Naismith A. , Biggs J. , Ordoñez P. A. , Boogher R. M. , Roca A.
Published: September 2021

Satellite radar backscatter has the potential to provide useful information about the progression of volcanic eruptions when optical, ground‐based, or radar phase‐based measurements are limited. However, backscatter changes are complex and challenging to interpret: explosive deposits produce different signals depending on pre‐existing ground cover, radar parameters and eruption characteristics. We use high temporal‐ and spatial‐resolution backscatter imagery to examine the emplacement and alteration of pyroclastic density currents (PDCs), lahar and ash deposits from the June 2018 eruption of Volcán de Fuego, Guatemala, using observatory reports and rainfall gauge data to ground truth our observations. We use a temporally dense time series of backscatter data to reduce noise and extract deposit areas. We observe backscatter changes in six drainages, the largest deposit was 11.9‐km‐long that altered an area of 6.3 and had a thickness of 10.5 2 m in the lower sections as estimated from radar shadows. The 3 June eruption also produced backscatter signal over an area of 40 , consistent with reported ashfall. We use transient patterns in backscatter time series to identify nine periods of high lahar activity in a single drainage system between June and October 2018. We find that the characterization of subtle backscatter signals associated with explosive eruptions are best observed with (1) radiometric terrain calibration, (2) speckle correction, and (3) consideration of pre‐existing scattering properties. Our observations demonstrate that SAR backscatter can capture the emplacement and subsequent alteration of a range of explosive deposits, allowing the progression of an explosive eruption to be monitored.
Future Climatic Projections and Hydrological Responses in the Upper Beijiang River Basin of South China Using Bias‐Corrected RegCM 4.6 Data
Authors: Chen Xiaoli , Chen Wenjie , Huang Guoru
Published: September 2021

The adverse effects of climate change on future extreme rainfall‐runoff events are posing severe challenges to flood control departments. Aimed at projecting future extreme rainfall‐runoff events over the Upper Beijiang River Basin of South China, regional climate model (RegCM 4.6) was used for dynamic downscaling three global climate models (GCMs) with two representative concentration pathways (RCP4.5 and RCP8.5) in two future periods (F1: 2016–2035 and F2: 2066–2085). Precipitation bias correction was carried out using an improved quantile mapping method. The future extreme precipitation events were analyzed using four extreme precipitation indices. The Soil and Water Assessment Tool model was established to simulate historical runoff and project future runoff. Three extreme runoff indices were defined to analyze future extreme runoff. The results showed that the bias correction effect was obvious, and the ability of the RegCM outputs driven by GCMs to capture the precipitation characteristics was obviously enhanced. Future extreme precipitation events will be more intense with almost all the four extreme precipitation indices showing increasing trends in future periods. Moreover, the future monthly runoff have basically increased and almost all the extreme runoff indices have increased in future periods with the average annual runoff, the total runoff in very wet days and the number of very heavy runoff days increasing by about 7%, 25%, and 35% respectively. Overall, responses and mitigation strategies should be developed regarding future extreme rainfall‐runoff events.
Impact of Prior Terrestrial Carbon Fluxes on Simulations of Atmospheric CO2 Concentrations
Authors: Fu Yu , Liao Hong , Tian XiangJun , Gao Hao , Jia Binghao , Han Rui
Published: September 2021

Terrestrial ecosystems have a significant role in shaping the distribution of atmospheric CO2, but it is uncertain how much they affect CO2 concentrations. We assessed the impact of terrestrial fluxes derived from different biosphere models in the Multi‐scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) on atmospheric CO2 estimations based on a global chemical transport model (GEOS‐Chem) when these fluxes were applied as prior information. We examined the spatiotemporal uncertainty in terrestrial flux estimations from 15 MsTMIP terrestrial fluxes. We found high uncertainties in the terrestrial fluxes for temperate North America, tropical and temperate South America, southern Africa, Europe and tropical Asia. Sensitivity simulations showed that the annual mean CO2 concentration changed by 6.0–8.0 ppmv with the spread of the terrestrial fluxes. The interannual trend in the terrestrial fluxes could significantly affect the simulated trend of atmospheric CO2 concentrations. As a result of the spread in the prior terrestrial fluxes, large differences in the daily mean CO2 anomalies changed with an interquartile range of −1.0 to +1.0 ppmv and the magnitude of change in the sub‐daily CO2 concentrations was in the range 4.0–6.0 ppmv for China, the USA and Europe. Our results suggest an urgent need to increase the reliability of terrestrial flux estimates in CO2 simulations. Surface seasonal CO2 concentrations were simulated to change by ±2.0 ppmv in most regions of the world due to the differences in the ensemble mean fluxes, reflecting the impact of the uncertainties in the existing optimized terrestrial fluxes on CO2 simulations.
Seasonality in Prediction Skill of the Madden‐Julian Oscillation and Associated Dynamics in Version 2 of NASA's GEOS‐S2S Forecast System
Authors: Lim Young‐Kwon , Arnold Nathan P. , Molod Andrea M. , Pawson Steven
Published: September 2021

The prediction skill of the Madden‐Julian Oscillation (MJO) in Version 2 of NASA's Global Earth Observing System Subseasonal to Seasonal (GEOS‐S2S) forecast system is investigated for winter and summer focusing on moistening‐related processes crucial for eastward propagating MJO activity. It is found that the annual bivariate correlation of the Real‐time Multivariate MJO time series between prediction and observation is ∼0.70, ∼0.57, and ∼0.50 at 20‐, 25‐, and 30‐day forecast leads. Correlation at long‐leads (>30 days) is noticeably higher for boreal summer initial conditions (June‐September [JJAS]), with correlations remaining above 0.5 at 35–40 days leads. Correlations are lower for boreal winter initial conditions from January through March (JFM), dropping to ∼0.5 at 25‐day lead, still comparable to the skills in the other reliable S2S forecast systems.

The predicted eastward MJO propagation across the Indo‐western Pacific sector is well captured in JJAS, but is slower than observed in JFM. Investigations of the moisture field and advection and moisture sink, moist static energy (MSE) budget, and tropical circulation/pressure responses to the MJO convective heating reveal that, in JFM, those responses and moistening processes, especially the vertical MSE advection, are underestimated over and to the east of the Maritime Continent when the MJO anomaly approaches from the west. In contrast, those processes are well represented in JJAS, although moistening is overestimated due to large surface evaporation. This study suggests that improvement of the moistening tendency over that region in the boreal winter could contribute to further increases in MJO prediction skill of the GEOS‐S2S system.
New Estimation of the NOx Snow‐Source on the Antarctic Plateau
Authors: Barbero A. , Savarino J. , Grilli R. , Blouzon C. , Picard G. , Frey M. M. , Huang Y. , Caillon N.
Published: September 2021

To fully decipher the role of nitrate photolysis on the atmospheric oxidative capacity in snow‐covered regions, NOx flux must be determined with more precision than existing estimates. Here, we introduce a method based on dynamic flux chamber measurements for evaluating the NOx production by photolysis of snowpack nitrate in Antarctica. Flux chamber experiments were conducted for the first time in Antarctica, at the French‐Italian station Concordia, Dome C (75°06'S, 123°20’E, 3233 m a.s.l) during the 2019–2020 summer campaign. Measurements were gathered with several snow samples of different ages ranging from newly formed drifted snow to 6‐year‐old firn. Contrary to existing literature expectations, the daily average photolysis rate coefficient, , did not significantly vary between differently aged snow samples, suggesting that the photolabile nitrate in snow behaves as a single‐family source with common photochemical properties, where a = (2.37 0.35) × 10−8 s−1 (1) has been calculated from December 10th 2019 to January 7th 2020. At Dome C summer daily average NOx flux, , based on measured NOx production rates was estimated to be (4.3 1.2) × 108 molecules cm−2 s−1, which is 1.5–7 times less than the net NOx flux observed previously above snow at Dome C using the gradient flux method. Using these results, we extrapolated an annual continental snow sourced NOx budget of 0.017 0.003 TgN y−1, 2 times the nitrogen budget, (N‐budget), of the stratospheric denitrification previously estimated for Antarctica. These quantifications of nitrate photolysis using flux chamber experiments provide a road‐map toward a new parameterization of the product that can improve future global and regional models of atmospheric chemistry.
Accessing the Subsurface Biosphere Within Rocks Undergoing Active Low‐Temperature Serpentinization in the Samail Ophiolite (Oman Drilling Project)
Authors: Templeton Alexis S. , Ellison Eric T. , Glombitza Clemens , Morono Yuki , Rempfert Kaitlin R. , Hoehler Tori M. , Zeigler Spencer D. , Kraus Emily A. , Spear John R. , Nothaft Daniel B. , Fones Elizabeth M. , Boyd Eric S. , Munro‐Ehrlich Mason , Mayhew Lisa E. , Cardace Dawn , Matter Juerg M. , Kelemen Peter B. ,   the Oman Drilling Project Science Party
Published: September 2021

The Oman Drilling Project established an “Active Alteration” multi‐borehole observatory in peridotites undergoing low‐temperature serpentinization in the Samail Ophiolite. The highly serpentinized rocks are in contact with strongly reducing fluids. Distinct hydrological regimes, governed by differences in rock porosity and fracture density, give rise to steep redox (Eh +200 to −750 mV) and pH (pH range 8.5–11.2) gradients within the 300–400 m deep boreholes. The serpentinites and fluids host an active subsurface ecosystem. Microbial cell abundances in serpentinite vary at least six orders of magnitude, from ≤3.5 × 101 to 2.9 × 107 cells/g. Low levels of biological sulfate reduction (2–1,000 fmol/cm3/day) can be detected in rock cores, particularly in rocks in contact with reduced groundwaters with pH < 10.5. Thermodesulfovibrio is the predominant sulfate reducer identified via metagenomic sequencing of adjacent groundwater communities. We infer that transport and reaction of microbially generated sulfide with the serpentine and brucite assemblages gives rise to optical darkening and sulfide overprinting, including the formation of tochilinite‐vallerite group minerals, potentially serving as an indicator that this system is inhabited by microbial life. Olivine mesh‐cores replaced with ferroan brucite and minor awaruite, abundant veins containing hydroandradite garnet and polyhedral serpentine, and late‐stage carbonate veins are suggested as targets for future spatially resolved life‐detection investigations. The high‐quality whole‐round core samples that have been preserved can be further probed to define how life distributes itself and functions within a system where chemical disequilibria are sustained by low‐temperature water/rock interaction, and how biosignatures of in situ microbial activity are generated.
Semi‐Coupling of a Field‐Scale Resolving Land‐Surface Model and WRF‐LES to Investigate the Influence of Land‐Surface Heterogeneity on Cloud Development
Authors: Simon Jason S. , Bragg Andrew D. , Dirmeyer Paul A. , Chaney Nathaniel W.
Published: September 2021

Contemporary Earth system models mostly ignore the sub‐grid scale (SGS) heterogeneous coupling between the land surface and atmosphere. To aid in the development of coupled land and atmosphere SGS parameterizations for global models, we present a study of different aspects of highly realistic sub‐100 km scale land‐surface heterogeneity. The primary experiment is a set of simulations of September 24, 2017 over the Southern Great Plains (SGP) site using the Weather Research and Forecasting (WRF) model with 100‐m horizontal resolution. The overall impact of land‐surface heterogeneity is evaluated by comparing cloud and turbulent kinetic energy (TKE) production in large‐eddy simulations (LESs) using heterogeneous and homogeneous surface fields (namely sensible and latent heat fluxes) specified by an offline field‐scale resolving land‐surface model (LSM). The heterogeneous land surface leads to significantly more cloud and TKE production. We then isolate specific sources of heterogeneity by using selectively domain‐wide averaged fields in the LSM. It is found that heterogeneity in the land surface created by precipitation is effectively responsible for the increases in cloud and TKE production, while rivers and soil type have a negligible impact and land cover has only a small impact. Additional experiments modify the Bowen ratio in the surface fields and the initial wind profile of the heterogeneous case to clarify the results seen. Finally two additional days at the SGP site are simulated showing a similar increase in cloud production in heterogeneous cases.
Attribution of Snowpack Errors to Simulated Temperature and Precipitation in E3SMv1 Over the Contiguous United States
Authors: Brunke Michael A. , Welty Joshua , Zeng Xubin
Published: September 2021

Snow water equivalent (SWE), temperature, and precipitation biases and trends are evaluated in the atmosphere‐land simulations of the Energy Exascale Earth System Model version 1 (E3SMv1) in comparison to the Community Earth System Model version 2 (CESM2) and two other models using the ground measurement‐based University of Arizona (UA) snow product. SWE, temperature, and precipitation biases are highest in magnitude in the Western contiguous United States (CONUS). SWE errors are attributed to temperature and precipitation through multiple linear regressions of normalized errors, the coefficients of which represent the sensitivities to temperature and precipitation errors. SWE errors are more sensitive to temperature errors throughout the CONUS. Model SWE and temperature trends are generally opposite from UA product trends in the Western CONUS. SWE trend errors are also attributed to temperature and precipitation trend errors using multiple linear regressions of normalized trend errors. SWE trend errors are more sensitive to those of precipitation at higher elevations (>1,500 m) in the Western CONUS in these simulations. Thus, the sensitivity to temperature and precipitation differ for SWE errors and its trend errors. Furthermore, the SWE trend errors are more sensitive to temperature and precipitation in the atmosphere‐ocean coupled simulations in which the atmosphere‐land is coupled to an active ocean model. These results suggest that both errors in simulated temperature and precipitation contribute to SWE errors.
Historical Reconstruction of Astronaut Cancer Risk: Context for Recent Solar Minima
Authors: Slaba Tony C.
Published: September 2021

As NASA prepares for longer duration missions beyond the geomagnetic field, the possibility of intensifying galactic cosmic ray (GCR) exposure raises possible concerns for mission planning and crew health and safety. Spaceborne satellite measurements have exhibited increasing GCR intensities and dose‐rates over the past few solar minima, consistent with related heliospheric magnetic field data. Surrogate measures of solar activity (e.g., sunspot number records and radionuclide yields from ice cores and/or tree rings) combined with model predictions have also been used to infer that the Sun may be entering into a quiet period similar to the Dalton or Gleissberg minima when GCR fluences reached historically high levels. Using the most up‐to‐date models for characterizing the ambient GCR environment, physical interactions with shielding, and cancer risk, it is found that projected risks vary by only ±10% over all historical minima since 1750. To provide additional context for this level of variation, two different nuclear interaction models are used within the radiation transport algorithms used to propagate GCR ions and secondary particles through shielding and tissue. It is shown that switching the nuclear interaction model also introduces 10% difference, on average, in projected risks over all historical minima. Furthermore, it is noted that the quantified historical variation is within combined environmental and physics uncertainties already accounted for in the probabilistic cancer risk model used by NASA for crew health and safety considerations.
Stochastic Rainwater Harvesting System Modeling Under Random Rainfall Features and Variable Water Demands
Authors: Cheng Guanhui , Huang Guohe (Gordon) , Guo Yiping , Baetz Brian W. , Dong Cong
Published: September 2021

A stochastic rainwater harvesting system modeling (StRaHaS) method is developed to enhance both accurateness and applicability of hydrologic modeling in guiding extensive applications of individual rainwater harvesting (RWH) systems (especially over large data‐scarce regions). The reliability of a RWH system is characterized as the fraction of time water demands being satisfied by a rainwater storage unit (RWSU). The variations of water balances, the post‐rainfall RWSU full‐storage probability, and the system reliability with random rainfall features, variable water demands, and the other RWH system characteristics are derived as analytical, accurate, and easily applied models through stochastic integration. StRaHaS is applied to three domestic RWH systems in Toronto, Canada. Due to high accurateness and low complexity in modeling, designing, assessing, and analyzing the RWH systems, StRaHaS outperforms existing methods (e.g., inaccurate water‐balance estimation, complicated continuous simulation, and simplified stochastic simulation). Based on StRaHaS, we quantitatively expound the increases in the reliability of the systems with higher rainwater supplies (corresponding to higher rainfall depths, and lower rainfall losses and first‐flush depths), lower water demands (in shorter wet and dry periods), and higher RWSU capacities. Long dry periods are lengthened by climate change and play dominant roles in low, spatially heterogeneous reliability of the systems. Synchronic changes and extremely high values of rainfall features do not significantly affect the reliability. Overall, StRaHaS is a promising method in modeling RWH systems, revealing RWH mechanisms, scientizing RWH applications, and facilitating the Sustainable Development Goals for addressing global water issues.
Prevalence of comorbidities and secondary health conditions among the Finnish population with spinal cord injury
Authors: Tallqvist Susanna , Kauppila Anna-Maija , Vainionpää Aki , Koskinen Eerika , Bergman Paula , Anttila Heidi , Hämäläinen Harri , Täckman Anni , Kallinen Mauri , Arokoski Jari , Hiekkala Sinikka
Published: September 2021

Study design

A cross-sectional study.

Objectives

To explore the prevalence of comorbidities, secondary health conditions (SHCs), and multimorbidity in the Finnish population with spinal cord injury (SCI).

Setting

The data were collected from the Finnish Spinal Cord Injury Study (FinSCI). Participants were identified from three SCI outpatient clinics responsible for the lifelong follow-up of persons with SCI in Finland, (n = 884 participants, response rate; 50%).

Methods

The FinSCI-questionnaire included a question from the National Study of Health, Well-being, and Service (FinSote) for screening 12 comorbidities. The reference data of the general population for that question were received from the Finnish Institute for Health and Welfare. The Spinal Cord Injury Secondary Condition Scale (SCI-SCS) was used to screen 16 SHCs. The data were analysed with univariate testing and multivariable negative binomial regression modelling.

Results

The most common comorbidities were high blood pressure/hypertension (38%), back problems (28%), and high cholesterol (22%). The most common SHCs were joint and muscle pain (81%), muscle spasms (74%), chronic pain (71%), and bowel problems (71%). The prevalence of comorbidities was highest among persons aged ≥76 years (mean; 2.0; scale range; 0–12). The prevalence of SHCs was highest in the severity of SCI group C1–4 AIS A, B, and C (mean; 8.9; scale range; 0–16).

Conclusions

Further research on geriatrics in SCI, non-traumatic SCI, and knowledge of the needs of persons with cervical lesion AIS A, B, or C is required, due to the fact that the prevalence of multimorbidity is high in these groups.
Non-diphtheriae Corynebacterium species are associated with decreased risk of pneumococcal colonization during infancy
Authors: Kelly Matthew S , Plunkett Catherine , Yu Yahe , Aquino Jhoanna N , Patel Sweta M , Hurst Jillian H , Young Rebecca R , Smieja Marek , Steenhoff Andrew P , Arscott-Mills Tonya , Feemster Kristen A , Boiditswe Sefelani , Leburu Tirayaone , Mazhani Tiny , Patel Mohamed Z , Rawls John F , Jawahar Jayanth , Shah Samir S , Polage Christopher R , Cunningham Coleen K , Seed Patrick C
Published: September 2021

Streptococcus pneumoniae (pneumococcus) is a leading cause of severe infections among children and adults. Interactions between commensal microbes in the upper respiratory tract and S. pneumoniae are poorly described. In this study, we sought to identify interspecies interactions that modify the risk of S. pneumoniae colonization during infancy and to describe development of the upper respiratory microbiome during infancy in a sub-Saharan African setting. We collected nasopharyngeal swabs monthly (0–6 months of age) or bimonthly (6–12 months of age) from 179 mother–infant dyads in Botswana. We used 16S ribosomal RNA gene sequencing to characterize the nasopharyngeal microbiome and identified S. pneumoniae colonization using a species-specific PCR assay. We detect S. pneumoniae colonization in 144 (80%) infants at a median age of 71 days and identify a strong negative association between the relative abundance of the bacterial genera Corynebacterium within the infant nasopharyngeal microbiome and the risk of S. pneumoniae colonization. Using in vitro cultivation experiments, we demonstrate growth inhibition of S. pneumoniae by secreted factors from strains of several Corynebacterium species isolated from these infants. Finally, we demonstrate that antibiotic exposures and the winter season are associated with a decline in the relative abundance of Corynebacterium within the nasopharyngeal microbiome, while breastfeeding is associated with an increase in the Corynebacterium relative abundance. Our findings provide novel insights into the interspecies interactions that contribute to colonization resistance to S. pneumoniae and suggest that the nasopharyngeal microbiome may be a previously unrecognized mechanism by which environmental factors influence the risk of pneumococcal infections during childhood. Moreover, this work lays the foundation for future studies seeking to use targeted manipulation of the nasopharyngeal microbiome to prevent infections caused by S. pneumoniae.
Autophagy-competent mitochondrial translation elongation factor TUFM inhibits caspase-8-mediated apoptosis
Authors: Choi Chang-Yong , Vo Mai Tram , Nicholas John , Choi Young Bong
Published: September 2021

Mitochondria support multiple cell functions, but an accumulation of dysfunctional or excessive mitochondria is detrimental to cells. We previously demonstrated that a defect in the autophagic removal of mitochondria, termed mitophagy, leads to the acceleration of apoptosis induced by herpesvirus productive infection. However, the exact molecular mechanisms underlying activation of mitophagy and regulation of apoptosis remain poorly understood despite the identification of various mitophagy-associated proteins. Here, we report that the mitochondrial translation elongation factor Tu, a mitophagy-associated protein encoded by the TUFM gene, locates in part on the outer membrane of mitochondria (OMM) where it acts as an inhibitor of altered mitochondria-induced apoptosis through its autophagic function. Inducible depletion of TUFM potentiated caspase-8-mediated apoptosis in virus-infected cells with accumulation of altered mitochondria. In addition, TUFM depletion promoted caspase-8 activation induced by treatment with TNF-related apoptosis-inducing ligand in cancer cells, potentially via dysregulation of mitochondrial dynamics and mitophagy. Importantly, we revealed the existence of and structural requirements for autophagy-competent TUFM on the OMM; the GxxxG motif within the N-terminal mitochondrial targeting sequences of TUFM was required for self-dimerization and mitophagy. Furthermore, we found that autophagy-competent TUFM was subject to ubiquitin-proteasome-mediated degradation but stabilized upon mitophagy or autophagy activation. Moreover, overexpression of autophagy-competent TUFM could inhibit caspase-8 activation. These studies extend our knowledge of mitophagy regulation of apoptosis and could provide a novel strategic basis for targeted therapy of cancer and viral diseases.
More knowledge causes a focused attention deployment pattern leading to lower creative performances
Authors: Yang Kunhao , Fujisaki Itsuki , Ueda Kazuhiro
Published: September 2021

Previous studies demonstrate that people with less professional knowledge can achieve higher performance than those with more professional knowledge in creative activities. However, the factors related to this phenomenon remain unclear. Based on previous discussions in cognitive science, we hypothesised that people with different amounts of professional knowledge have varying attention deployment patterns, leading to different creative performances. To examine our hypothesis, we analysed two datasets collected from a web-based survey and a popular online shopping website, Amazon.com (United States). We found that during information processing, people with less professional knowledge tended to give their divided attention, which positively affected creative performances. Contrarily, people with more professional knowledge tended to give their concentrated attention, which had a negative effect. Our results shed light on the relation between the amount of professional knowledge and attention deployment patterns, thereby enabling a deeper understanding of the factors underlying the different creative performances of people with varying amounts of professional knowledge.
Non-destructive raman spectroscopic determination of freshwater mollusk composition, growth, and damage repair
Authors: Sarabia Grace M. , Sharma Bhavya
Published: September 2021

Raman spectroscopy shows great promise for monitoring mollusk shell composition, shell growth and repair.
ZnO/CoS heterostructured nanoflake arrays vertically grown on Ni foam for high-rate supercapacitors
Authors: Chen Haijun , Xiao Shuhao , Li Yun-ze , Ma Xudong , Huang Yan , Wang Yan , Chen Jun Song , Feng Zhe-sheng
Published: September 2021

The ZnO NFAs/CoS NFs heterostructure exhibits excellent supercapacitor performance and its electron transfer mechanism is studied by DFT.
ON/OFF metal-triggered molecular tweezers for fullerene recognition
Authors: Sacristán-Martín Adriana , Barbero Héctor , Ferrero Sergio , Miguel Daniel , García-Rodríguez Raúl , Álvarez Celedonio M.
Published: September 2021

Turning on the corannulene: fully reversible and quantitative switching of ON/OFF states for fullerene recognition achieved by metal coordination.
Investigation of various fatty acid surfactants on the microstructure of flexible hydroxyapatite nanofibers
Authors: Wang Yin-chuan , Wang Jian-ning , Xiao Gui-yong , Huang Sheng-yun , Xu Wei-li , Yan Wen-xi , Lu Yu-peng
Published: September 2021

The synthesis of hydroxyapatite nanofibers using various fatty acids and their influences on HA crystal characteristics were systematically explored.
Research progress in the enhancement technology of soil vapor extraction of volatile petroleum hydrocarbon pollutants
Authors: Cao Weikai , Zhang Lei , Miao Yue , Qiu Lufan
Published: September 2021

At present, volatile petroleum hydrocarbon pollution in soil is still widespread and serious in China.