bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of the Thebe Extension in the Ring System of Jupiter
Authors: Borisov N. , Krüger H. 
Published: October 2021

AbstractJupiter's tenuous dust ring system is embedded in the planet's inner magnetosphere, and—among other structures—contains a very tenuous protrusion called the Thebe extension. In an attempt to explain the existence of this swath of particles beyond Thebe's orbit, Hamilton and Krüger (2008), https://doi.org/10.1038/nature06886 proposed that the dust particle motion is driven by a shadow resonance caused by variable dust charging on the day and night side of Jupiter. However, the model by Divine and Garrett (1983), https://doi.org/10.1029/ja088ia09p06889 together with recent observations by the Juno spacecraft indicates a warm and rather dense inner magnetosphere of Jupiter which implies that the mechanism of the shadow resonance does not work. Instead, we argue that dust grains ejected from Thebe due to micrometeoroid bombardment become the source of dust in the Thebe extension. We show that large (grain radii of a few micrometers up to multi‐micrometers) charged dust grains having significant initial velocities oscillate in the Thebe extension. Smaller charged grains (with sub‐micrometer radii) ejected from Thebe do not spend much time in the Thebe extension and migrate into the Thebe ring. At the same time, if such grains are ejected from larger dust grains in the Thebe extension due to fragmentation, they continue to oscillate within the Thebe extension for years. We argue that fragmentation of large dust grains in the Thebe extensions could be the main source of sub‐micrometer grains detected in the Thebe extension.
Examining the Auroral Ionosphere in Three Dimensions Using Reconstructed 2D Maps of Auroral Data to Drive the 3D GEMINI Model
Authors: Clayton Robert , Burleigh Meghan , Lynch Kristina A. , Zettergren Matt , Evans Tucker , Grubbs Guy , Hampton Donald L. , Hysell David , Kaeppler Stephen , Lessard Marc , Michell Robert , Reimer Ashton , Roberts T.  Maximillian , Samara Marilia , Varney Roger 
Published: October 2021

AbstractWe use the Geospace Environment Model of Ion‐Neutral Interactions (GEMINI) to create three‐dimensional, time‐dependent simulations of auroral ionospheric parameters in the localized, several 100 km region surrounding auroral arcs observed during a winter 2017 sounding rocket campaign, resolving three‐dimensional features of fine‐scale (km) flow structures in the vicinity of an auroral arc. The three‐dimensional calculations of GEMINI allow (with sufficient driving data) auroral current closure to be investigated without idealizing assumptions of sheet‐like structures or height integrated ionospheres. Datamaps for two nearly sheet‐like arcs are reconstructed from replications of the Isinglass sounding rocket campaign data, and combined with camera‐based particle inversions into a set of driving inputs to run the 3D time‐dependent model. Comparisons of model results to radar density profiles and to in situ magnetometry observations are presented. Slices of volumetric current, flow, and conductance structures from model outputs are used to interpret closure currents in an auroral arc region, and are compared to original in situ measurements for verification. The predominant source of return current region field aligned current closure for these slow time variation events is seen to be from the conductance gradients, including the Hall. The importance of the versus terms in the determination of the current structure provides a more complicated picture than a previous GEMINI study, which relied predominantly on the divergence of the electric field to determine current structure. Sensitivity of data‐driven model results to details of replication and reconstruction processes are discussed, with improvements outlined for future work.
A Compound Faulting Model for the 1975 Kalapana, Hawaii, Earthquake, Landslide, and Tsunami
Authors: Yamazaki Yoshiki , Lay Thorne , Cheung Kwok Fai 
Published: October 2021

AbstractThe Kalapana, Hawaii, MW 7.7 earthquake on November 29, 1975 generated a local tsunami with at least 14.3 m runup on the southeast shore of Hawaii Island adjacent to Kilauea Volcano. This was the largest locally generated tsunami since the great 1868 Ka'u earthquake located along‐shore to the southwest. Well‐recorded tide gauge and runup observations provide a key benchmark for studies of statewide tsunami hazards from actively deforming southeast Hawaii Island. However, the source process of the earthquake remains controversial, with coastal landsliding and/or offshore normal or thrust faulting mechanisms having been proposed to reconcile features of seismic, geodetic, and tsunami observations. We utilize these diverse observations for the 1975 Kalapana earthquake to deduce a compound faulting model that accounts for the overall tsunamigenesis, involving both landslide block faulting along the shore and slip on the island basal décollement. Thrust slip of 4.5–8.0 m on the offshore décollement produces moderate near‐field runup but controls the far‐field tsunami. The slip distribution implies that residual strain energy was available for the May 4, 2018 MW 7.2 thrust earthquake during the Kilauea‐East Rift Zone eruption. Local faulting below land contributes to geodetic and seismic observations, but is non‐tsunamigenic and not considered. Slip of 4–10 m on landslide‐like faults, which extend from the Hilina Fault Zone scarp to offshore shallowly dipping faults reaching near the seafloor, triples the near‐field tsunami runup. This compound model clarifies the roles of the faulting components in assessing tsunami hazards for the Hawaiian Islands.
Influence of Dust on Precipitation During Landfalling Atmospheric Rivers in an Idealized Framework
Authors: Mascioli N. R. , Evan A. T. , Ralph F. M. 
Published: October 2021

AbstractAtmospheric rivers (ARs) can provide as much as 50% of the total annual rainfall to the United States West Coast via orographic precipitation. Dust is thought to enhance orographic precipitation via the “seeder‐feeder” mechanism, in which ice particles from a high cloud fall through a lower orographic cloud, seeding precipitation in the low cloud. Using the Weather Research and Forecasting model, we vary dust concentrations in simulations of two‐dimensional flow over a mountain. This idealized framework allows us to test the sensitivity of the precipitation‐dust response to a variety of different dust concentrations and initial conditions. The model is run using an ensemble of 60 radiosondes collected from Bodega Bay, CA in 2017–2018, clustered based on their vertical moisture profile into “deep moist,” “shallow moist,” and “subsaturated” clusters. The principle impact on precipitation is to increase the ratio of precipitation falling as snow. This produces a “spillover” effect, decreasing precipitation upwind of the peak and increasing precipitation downwind of the peak. The largest impacts on the snow/rain ratio occur at the end of the event, during cold front passage. The ensemble mean does not produce a significant seeder‐feeder response, however, in individual cases with favorable initial conditions there is a significant increase in precipitation throughout the domain due to dust effects on the seeder‐feeder mechanism. These findings afford an opportunity to build a more comprehensive understanding for the conditions under which dust aerosol can have a significant impact on precipitation during ARs, with implications for future developments in forecasting.
Instantaneous Habitable Windows in the Parameter Space of Enceladus' Ocean
Authors: Higgins Peter M. , Glein Christopher R. , Cockell Charles S. 
Published: October 2021

AbstractIn recent years, Enceladus' subsurface ocean has become a tantalizing case study for potentially habitable conditions in an extraterrestrial ocean world. However, we still know very little about its subsurface conditions. Its oceanic composition is difficult to characterize with current data and estimates are highly dependent on model‐based interpretations which are also not yet tightly constrained. In light of these uncertainties, we consider a wide selection of the inferred parameter spaces to quantify the energy available to putative hydrogenotrophic methanogens on Enceladus in the bulk ocean at cool and elevated temperatures. We estimate the instantaneous power supply their metabolism could provide in these conditions and compare it to the expected power demands of life on Earth. To be habitable for methanogens a 273 K ocean with relatively high salt content must have pH 10, and a relatively low salt ocean must have pH 8 at 273 K, or pH 9 when heated to 360 K. Some combinations meet the power demands of exponential growth, but large swathes of the parameter space appear energetically uninhabitable. The habitability of the Enceladus ocean for methanogens appears to be a delicate balance between its temperature, pH, salinity, and concentrations of carbonates, nutrients, and dissolved gases (particularly ). Many of these parameters are co‐dependent; variation in any one of them could tip the balance into uninhabitable conditions. Further constraining these variables should be a priority for future missions to ocean worlds to enable definitive assessments of their habitability.
Specific Heat Capacity Measurements of Selected Meteorites for Planetary Surface Temperature Modeling
Authors: Piqueux Sylvain , Vu Tuan H. , Bapst Jonathan , Garvie Laurence A. J. , Choukroun Mathieu , Edwards Christopher S. 
Published: October 2021

AbstractSpecific heat capacity Cp(T) is an intrinsic regolith property controlling planetary surface temperatures along with the albedo, density, and thermal conductivity. Cp(T) depends on material composition and temperature. Generally, modelers assume a fixed specific heat capacity value, or a standard temperature dependence derived from lunar basalts, mainly because of limited composition‐specific data at low temperatures relevant to planetary surfaces. In addition, Cp(T) only appears to vary by a small factor across various materials, in contrast with the bulk regolith thermal conductivity, which ranges over ∼3–4 orders of magnitude as a function of the regolith physical state (grain size, cementation, sintering, etc.). For these reasons, the impact of the basaltic assumption on modeled surface temperature is often considered unimportant although this assumption is not particularly well constrained. In this paper, we present specific heat capacity measurements and parameterizations from ∼90 to ∼290 K of 28 meteorites including those possibly originating from Mars and Vesta, and covering a wide range of planetary surface compositions. Planetary surface temperatures calculated using composition‐specific Cp(T) are within 2 K of model runs assuming a basaltic composition. This 2 K range approaches or exceeds typical instrumental noise or other sources of modeling uncertainties. These results suggest that a basaltic assumption for Cp(T) is generally adequate for the thermal characterization of a wide range of planetary surfaces, but possibly inadequate when looking at leveraging subtle trends to constrain subsurface layering, roughness, or seasonal/diurnal volatile transfer.
Higher Sensitivity of Planted Forests' Productivity Than Natural Forests to Droughts in China
Authors: Zhong Ziqian , He Bin , Chen Yaning , Yuan Wenping , Huang Ling , Guo Lanlan , Zhang Yafeng , Xie Xiaoming 
Published: October 2021

AbstractPlanted forests (PFs) account for about one‐third of the total area of forests in China and make important contributions to carbon sequestration and ecosystem services. Droughts pose a major threat to all forest ecosystems and yet, despite the importance of PFs, there is limited information about their sensitivity to drought and how it compares with that of natural forests (NFs). In this study, satellite‐based vegetation indices were used to investigate and compare the sensitivity of PFs and NFs to drought. We found that PFs' productivity was more sensitive to droughts than NFs, demonstrating a stronger correspondence to interannual variations in drought and a larger decline in productivity under drought conditions than NFs. However, PFs tended to recover more rapidly after drought disturbance than NFs. The observed differences in the sensitivity to droughts may reflect intrinsic differences between PF and NF ecosystems. We also found that the difference between the response of PFs and NFs to drought became less notable as the climate aridity increased, indicating influences from external environmental conditions. The findings from this study highlight the importance of increasing the resistance of PFs to climate change by various management strategies, giving special attention to water availability issues.
Algal‐Induced Biogeomorphic Feedbacks Lay the Groundwork for Coastal Wetland Development
Authors: van de Vijsel Roeland C. , van Belzen Jim , Bouma Tjeerd J. , van der Wal Daphne , van de Koppel Johan 
Published: October 2021

AbstractEcosystem establishment under adverse geophysical conditions is often studied within the “windows of opportunity” framework, identifying disturbance‐free periods (e.g., calm wave climate) where species can overcome establishment thresholds. However, the role of biogeophysical interactions in this framework is less well understood. The establishment of saltmarsh vegetation on tidal flats, for example, is limited by abiotic factors such as hydrodynamics, sediment stability and drainage. On tidal flats, raised sediment ridges colonized by algal mats (Vaucheria sp.) appear to accomodate high densities of plant seedlings. Such ridges were previously found to have higher sediment strength than substratum without algae. Here, we investigate whether these measurements can be explained by geophysical factors only, or that biological (Vaucheria‐induced) processes influence tidal marsh establishment by forming stabilized bedforms. We performed two experiments under controlled mesocosm conditions, to test the hypotheses that (a) Vaucheria grows better on elevated topographic relief, that (b) the binding force of their algal filaments increases sediment strength, and that (c) Vaucheria consequently creates elevated topographic relief that further facilitates algal growth. Our experimental results confirm the existence of this algal‐induced biogeomorphic feedback cycle. These findings imply that benthic algae like Vaucheria may contribute significantly to tidal marsh formation by creating elevated and stabilized substratum. This suggests biogeophysical feedbacks can “widen” the windows of opportunity for further ecosystem establishment. Our results could be useful for the design of managed realignment projects aimed at restoring the unique ecosystem services of coastal wetlands, such as habitat biodiversity, carbon sequestration potential and nature‐based flood defense.
Seasonal Dynamics of Surface Dissolved Organic Matter in the South China Sea and the Straits of Malacca: Implications for Biogeochemical Province Delineation of Marginal Seas
Authors: Zhang Yixue , Wu Ying , Zhang Jing , Jin Jie , Li Jian , Zhang Zhenqiu 
Published: October 2021

AbstractBiogeochemical provinces are an important aid to identify homogeneous biogeochemical characteristics and underlying ecosystem dynamics in the open ocean. This macroscale approach, however, does not appear to be applicable to marginal seas for disregarding various small scale changes. Here, we adopted two observation schemes throughout the typical marginal seas, the South China Sea (SCS) and Straits of Malacca (MS), with continuous surface‐water sampling during March and May 2018. Spatial and seasonal heterogeneity of hydrological and dissolved organic matter (DOM) properties was investigated. With a novel combination of chromophoric DOM index and classical biogeochemical parameters (temperature, salinity, chlorophyll‐a, and bathymetry), we delineated five biogeochemical provinces in each season to integrate DOM pools and investigate region‐specific and season‐dependent biogeochemical processes. The results showed that the SCS basin was seasonally modulated by biological activities and photodegradation, resulting in the biologically active DOM pools. The western SCS seasonally received terrestrial DOM, subjected to the western boundary current under monsoon regulation. The MS was found to serve as an efficient carbon source of terrestrial substances, which exported to the northern Indian Ocean during the Northeast Monsoon. The delineation favored the simplification of complex biogeochemistry and allowed us to predict future trends in this dynamic system. Chromophoric DOM index was proven applicable to the delineation of marginal seas, that shed the light on the potential applications in biogeochemical provinces in dynamic systems.
Model Evaluation and Intercomparison of Marine Warm Low Cloud Fractions With Neural Network Ensembles
Authors: Chen Yao‐Sheng , Yamaguchi Takanobu , Bogenschutz Peter A. , Feingold Graham 
Published: October 2021

AbstractLow cloud fractions (LCFs) and meteorological factors (MFs) over an oceanic region containing multiple cloud regimes are examined for three data sets: one Energy Exascale Earth System Model (E3SM) simulation with the default 72‐layer vertical grid (E3SM72), another one with 8‐times vertical resolution via the Framework for Improvement by Vertical Enhancement (E3SM8), and one with MFs from ERA5 reanalysis and LCFs from the CERES SSF product (ERA5‐SSF). Neural networks (NNs) are trained to capture the relationship between MFs and LCF and to select the best‐performing MF subsets for predicting LCF. NN ensembles are used to (a) confirm the performance of selected MF subsets, (b) to serve as proxy models for each data set to predict LCFs for MFs from all data sets, and (c) to classify MFs into those in shared and uniquely occupied MF subspaces. Overall, E3SM72 and E3SM8 have large fractions of MFs in shared MF subspace, but less so near the Californian and Peruvian stratocumulus decks. E3SM8 and ERA5 have small fractions of MFs in shared MF subspace but greater than E3SM72 and ERA5, especially in the Southeast Pacific. The differences in LCFs between three pairs of data sets are decomposed into those associated with the differences in the LCF‐MF relationship and those involving different MFs. Given the same MFs, LCFs produced by E3SM8 are greater than those produced by E3SM72 but are still different from those in ERA5‐SSF. In general, the shift in MFs dominates the difference in the LCFs.
Ionospheric Storm Scale Index Based on High Time Resolution UPC‐IonSAT Global Ionospheric Maps (IsUG)
Authors: Liu Qi , Hernández‐Pajares Manuel , Lyu Haixia , Nishioka Michi , Yang Heng , Monte‐Moreno Enric , Gulyaeva Tamara , Béniguel Yannick , Wilken Volker , Olivares‐Pulido Germán , Orús‐Pérez Raül 
Published: October 2021

AbstractThe ionospheric storms have adverse effects on the radio communications, satellite communications and also the Global Navigation Satellite Systems (GNSS) application. A new Ionospheric storm Scale from Universitat Politècnica de Catalunya (UPC) Global Ionosphere Map (GIM), IsUG, is introduced for characterizing the ionospheric state on a global scale. The IsUG is based on the Vertical Total Electron Content (VTEC) derived from the continuously computed UPC Quarter‐of‐an‐hour time resolution Rapid GIM (UQRG), taking as reference the ones during the period 1997 to 2014. It is similar to the I‐scale index previously introduced, although it was over Japan and based on raw GNSS data. The dependence of the VTEC on season, local time and geographical location at each grid point of UQRG is removed by normalizing (i.e., by substracting the mean and dividing by the corresponding standard deviation) the percentage deviation of hourly median VTEC. After validating IsUG versus I‐scale, the IsUG distribution is presented and analyzed at global scale during a severe geomagnetic storm from 7 to 10 November 2004 as an example of the potentialities of the new index. The results suggest that the IsUG global map has a great potential for the scientific study of ionospheric storms from a global perspective and also for space weather warning considering the accuracy of the recently developed real‐time GIMs.
Evaluation of associations between estimates of particulate matter exposure and new onset type 2 diabetes in the REGARDS cohort
Authors: McAlexander Tara P. , De Silva S. Shanika A. , Meeker Melissa A. , Long D. Leann , McClure Leslie A. 
Published: October 2021

Abstract
Background
Studies of PM2.5 and type 2 diabetes employ differing methods for exposure assignment, which could explain inconsistencies in this growing literature. We hypothesized associations between PM2.5 and new onset type 2 diabetes would differ by PM2.5 exposure data source, duration, and community type.

Methods
We identified participants of the US-based REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort who were free of diabetes at baseline (2003–2007); were geocoded at their residence; and had follow-up diabetes information. We assigned PM2.5 exposure estimates to participants for periods of 1 year prior to baseline using three data sources, and 2 years prior to baseline for two of these data sources. We evaluated adjusted odds of new onset diabetes per 5 µg/m3 increases in PM2.5 using generalized estimating equations with a binomial distribution and logit link, stratified by community type.

Results
Among 11,208 participants, 1,409 (12.6%) had diabetes at follow-up. We observed no associations between PM2.5 and diabetes in higher and lower density urban communities, but within suburban/small town and rural communities, increases of 5 µg/m3 PM2.5 for 2 years (Downscaler model) were associated with diabetes (OR [95% CI] = 1.65 [1.09, 2.51], 1.56 [1.03, 2.36], respectively). Associations were consistent in direction and magnitude for all three PM2.5 sources evaluated.

Significance
1- and 2-year durations of PM2.5 exposure estimates were associated with higher odds of incident diabetes in suburban/small town and rural communities, regardless of exposure data source. Associations within urban communities might be obfuscated by place-based confounding.
Aberrant neural representation of food stimuli in women with acute anorexia nervosa predicts treatment outcome and is improved in weight restored individuals
Authors: Boehm Ilka , Mohr Holger , King Joseph A. , Steding Julius , Geisler Daniel , Wronski Marie-Louis , Weigel Katharina , Roessner Veit , Ruge Hannes , Ehrlich Stefan 
Published: October 2021

AbstractAnorexia nervosa (AN) has been associated with altered reward processing. We recently reported greater neural response in secondary visual areas when processing visual food stimuli in acutely underweight AN patients (acAN). In order to examine whether the observed alterations are indicative of acute undernutrition or a potential trait marker of AN, we set out to assess neural responses in acAN and in individuals weight-recovered from AN (recAN). FMRI data were collected from a total of 126 female volunteers, 35 acAN, 33 recAN, and 58 age-matched healthy controls (HC) while they viewed streams of food, social and neutral stimuli. A standard general linear model (GLM) was used to interrogate neural responses to the different stimuli in recAN vs. age-matched HC. Moreover, within-subject multivoxel pattern analyses (MVPA) in the two matched samples (acAN/HC and recAN/HC) were used to estimate neural representation of food vs. neutral, and social vs. neutral stimuli. A multiple regression analysis was conducted to test associations between the accuracy of the neural representation and treatment outcome. The GLM revealed no group differences between recAN and HC. The MVPAs showed greater classification accuracy of food stimuli in the posterior fusiform gyrus in acAN but not recAN. Classification accuracy was associated with better treatment outcome. Our findings suggest that the neural representation of food stimuli is altered in secondary visual areas in acAN and normalizes with weight recovery. Possibly this altered representation reflects attentional engagement motivating food intake, which may promote the recovery process.