bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wave Dissipation by Bottom Friction on the Inner Shelf of a Rocky Shore
Authors: Gon Casey J. , MacMahan Jamie H. , Thornton Edward B. , Denny Mark 
Published: September 2020

AbstractApproximately 32% of the measured wave energy flux by sea and swell waves was dissipated over distances less than 130 m, outside of wave breaking on the inner shelf, over a rocky shore in southern Monterey Bay, CA. The bottom roughness of the rocky shore is defined by the standard deviation of bottom vertical variability, σb, that is 0.9 m, which is of similar magnitude to previously measured σb for rough coral reefs. Spectral wave energy flux balanced by bottom friction is modeled and compared with observations. Measured average wave reflection was 0.08 and is neglected in the model. The average energy dissipation owing to bottom friction over the rocky shore results in energy friction factors, fe, ranging 4 to 34. The observed fe are larger than previously measured fe on coral reefs. An empirical power law relationship is developed for fe as a function of the ratio of wave orbital excursion amplitude, Ab, and σb, based on combined data from coral reefs, rocky platforms, and this rocky shore. As σb increases, fe increases. Numerical simulation by Yu et al. (2018, https://doi.org/10.9753/icce.v36.waves.57) of waves over large bottom variations, similar to observed on coral reefs, suggests that drag forces do not account for the large observed fe. Therefore, it is hypothesized that bottom friction on rocky shores is a function of multiscale physical and biological roughness.
Can Exploratory Modeling of Water Scarcity Vulnerabilities and Robustness Be Scenario Neutral?
Authors: Quinn J. D. , Hadjimichael A. , Reed P. M. , Steinschneider S. 
Published: September 2020

AbstractPlanning under deep uncertainty, when probabilistic characterizations of the future are unknown, is a major challenge in water resources management. Many planning frameworks advocate for “scenario‐neutral” analyses in which alternative policies are evaluated over plausible future scenarios with no assessment of their likelihoods. Instead, these frameworks use sensitivity analysis to discover which uncertain factors have the greatest influence on performance. This knowledge can be used to design monitoring programs and adaptive policies that respond to changes in the critical uncertainties. However, scenario‐neutral analyses make implicit assumptions about the range and independence of the uncertain factors that may not be consistent with the coupled human‐hydrologic processes influencing the system. These assumptions could influence which factors are found to be most important and which policies are most robust, belying their neutrality; assuming uniformity and independence could have decision‐relevant implications. This study illustrates these implications using a multistakeholder planning problem within the Colorado River Basin, where hundreds of rights holders vie for the river's limited water under the law of prior appropriation. Variance‐based sensitivity analyses are performed to assess users' vulnerabilities to changing hydrologic conditions using four experimental designs: (1) scenario‐neutral samples of hydrologic factors, centered on recent historical conditions, (2) scenarios informed by climate projections, (3) scenarios informed by paleohydrologic reconstructions, and (4) scenario‐neutral samples of hydrologic factors spanning all previous experimental designs. Differences in sensitivities and user robustness rankings across the experiments illustrate the challenges of inferring the most consequential drivers of vulnerabilities to design effective monitoring programs and robust management policies.
Interacting Infrastructure Disruptions Due to Environmental Events and Long‐Term Climate Change
Authors: Hummel Michelle A. , Tcheukam Siwe Alain , Chow Aaron , Stacey Mark T. , Madanat Samer M. 
Published: September 2020

AbstractClimate change places additional stress on critical infrastructure systems as demand for resources (e.g., water and electricity) increases and environmental disruptions (e.g., flooding and wildfires) become more frequent and severe. Interconnected infrastructure systems may be particularly vulnerable, as disruptions in one system can cascade to other systems and increase the severity of impacts. To ensure continued functionality, infrastructure systems must be designed or adapted to account for changing environmental conditions, with consideration for the interactions between systems. For this study, we examine the dependencies between shoreline protective infrastructure and transportation infrastructure in the context of sea level rise in the San Francisco Bay Area. Shoreline modifications implemented in one location can cause hydrodynamic feedbacks that exacerbate flooding and associated disruptions elsewhere. On the other hand, the decision not to implement shoreline protection can cause local flooding of roadways that leads to traffic feedbacks and system‐wide travel delays. We compare the magnitude of these feedbacks, in terms of vehicle hours traveled (VHT), across a range of county‐level shoreline scenarios to characterize the effects of one county's shoreline adaptation decisions on its neighbors. Our results show that VHT increases by as much as 7.2% due to hydrodynamic feedbacks and 10.7% due to traffic feedbacks. Comparing these effects for each scenario allows for targeted decision‐making about adaptation approaches that account for both the local effects of flood disruptions and the regional network effects driven by infrastructure interactions.
Thermal and Compositional Anomalies of the Australian Upper Mantle From Seismic and Gravity Data
Authors: Tesauro Magdala , Kaban Mikhail K. , Aitken Alan R. A. 
Published: September 2020

AbstractTo discern temperature and compositional variations of the Australian upper mantle, we apply an integrative technique, which jointly interprets seismic tomography and gravity data. The final thermal model, obtained by changing the upper mantle composition according to the density variations, shows temperatures higher by 100–150°C in the Archean and Proterozoic upper mantle, with respect to the initial model based on a uniform “fertile” composition. In the North and West Australian cratons, the upper mantle is cold, with composition depleted in heavy constituents. This suggests the presence of an Archean lithosphere, which remained relatively undisturbed through the Proterozoic. Central Australia is predominantly characterized by a thick, low‐temperature lithosphere having a more fertile composition. Its shallow part is characterized by a thin layer of low‐velocity mantle, which is interpreted by our results as a thermal anomaly. However, this high‐temperature anomaly is hard to reconcile with the tectonic history of the region. A low‐density mineral phase, such as amphibole, may reduce the density relative to our assumed composition. Furthermore, we observe larger iron depletion in the Western Australian Craton than in the Proterozoic terranes. At the depths larger than 150 km, the depletion becomes negligible beneath the Proterozoic regions, while it also persists in the Western Australian Craton at the depths larger than 200 km.
COVID‐19 Impact on the Concentration and Composition of Submicron Particulate Matter in a Typical City of Northwest China
Authors: Xu Jianzhong , Ge Xinlei , Zhang Xinghua , Zhao Wenhui , Zhang Ruixiong , Zhang Yuzhong 
Published: September 2020

AbstractIn this study, we evaluated the variations of air quality in Lanzhou, a typical city in Northwestern China impacted by the COVID‐19 lockdown. The mass concentration and chemical composition of non‐refractory submicron particulate matter (NR‐PM1) were determined by a high‐resolution aerosol mass spectrometer during January‐March 2020. The concentration of NR‐PM1 dropped by 50% from before to during control period. The five aerosol components (sulfate, nitrate, ammonium, chloride, and organic aerosol [OA]) all decreased during the control period with the biggest decrease observed for secondary inorganic species (70% of the total reduction). Though the mass concentration of OA decreased during the control period, its source emissions varied differently. OA from coal and biomass burning remained stable from before to during control period, while traffic and cooking related emissions were reduced by 25% and 50%, respectively. The low concentration during the control period was attributed to the lower production rate for secondary aerosols.
Suprathermal Electron Evolution Under the Competition Between Plasmaspheric Plume Hiss Wave Heating and Collisional Cooling
Authors: Wang Zhongshan , Su Zhenpeng , Liu Nigang , Dai Guyue , Zheng Huinan , Wang Yuming , Wang Shui 
Published: September 2020

AbstractSuprathermal electrons are a major heat source of ionospheric plasma. How the suprathermal electrons evolve during their bounces inside the plasmasphere is a fundamental question for the magnetosphere‐ionosphere coupling. On the basis of Van Allen Probes observations and quasi‐linear simulations, we present here the first quantitative study on the evolution of suprathermal electrons under the competition between Landau heating by whistler mode hiss waves and Coulomb collisional cooling by background plasma inside a plasmaspheric plume. We show that the Landau heating can prevail over the collisional cooling for >50 eV electrons and cause the field‐aligned suprathermal electron fluxes to increase by up to 1 order of magnitude within 1.5 hr. Our results imply that the plasmaspheric plume hiss waves could mediate energy from the ring current electrons to the ionospheric plasma.
Seasonal Effect on Hemispheric Asymmetry in Ionospheric Horizontal and Field‐Aligned Currents
Authors: Workayehu A. B. , Vanhamäki H. , Aikio A. T. 
Published: September 2020

AbstractWe present a statistical investigation of the seasonal effect on hemispheric asymmetry in the auroral currents during low (Kp < 2) and high (Kp ≥ 2) geomagnetic activity. Five years of magnetic data from the Swarm satellites has been analyzed by applying the spherical elementary current system (SECS) method. Bootstrap resampling has been used to remove the seasonal differences between the hemispheres in the data set. In general, the currents are larger in the Northern Hemisphere (NH) than in the Southern Hemisphere (SH). Asymmetry is larger during low than high Kp and during local winter and local autumn than local summer and local spring. For all Kp conditions together, the NH/SH ratio for FACs in winter, autumn, spring, and summer are 1.17 ± 0.05, 1.14 ± 0.05, 1.07 ± 0.04, and 1.02 ± 0.04, respectively. The largest asymmetry is observed during low Kp in local winter, when the excess in the NH currents is 21 ± 5% in FAC, 14 ± 3% in curl‐free (CF) and 10 ± 3% in divergence‐free (DF) current. We also find that evening sector (13–24 MLT) contributes more to the high NH/SH ratio than the morning (01–12 MLT) sector. The physical mechanisms producing the hemispheric asymmetry are not presently understood. We calculated the solar‐induced ionospheric conductances during low Kp conditions from the IRI model. The model conductance NH/SH ratios are above 1 in autumn and spring, similar to the currents, but below 1 for winter, which is in contradiction with the currents. Therefore, we do not consider solar‐induced conductances as the main explanation for hemispheric asymmetry.
Evaluation of Shipboard and Satellite‐Derived Bathymetry and Gravity Data Over Seamounts in the Northwest Pacific Ocean
Authors: Watts A. B. , Tozer B. , Harper H. , Boston B. , Shillington D. J. , Dunn R. 
Published: September 2020

AbstractEarth's surface topography/bathymetry and gravity fields provide important constraints on crustal structure and the tectonic processes that act on it due, for example, to plate flexure and mantle convection. Such studies require, however, high accuracy measurements at a wide range of spatial scales. During the past few decades much progress has been made in the acquisition of bathymetry and gravity data using both shipboard and satellite altimeter methods. Surprisingly, there have been few comparisons of these data. During April–June, 2019 we had the opportunity onboard a R/V Marcus G. Langseth cruise in the northwest Pacific Ocean to compare data acquired with an EM122 Kongsberg swath bathymetry system and a refurbished Bell Aerospace BGM‐3 gravimeter with the most recent global bathymetry and gravity fields. We find that while the recovery of bathymetry and gravity from satellite radar altimeter data in areas of sparse shipboard data has been impressive, root mean square discrepancies in the range 175.5–303.4 m and 2.6–6.3 mGal exist between shipboard and satellite‐derived data. While these discrepancies are small, they are highly correlated and therefore have implications for the density structure, rock type and geological processes occurring on the deep seafloor. Shipboard data should continue to be acquired, especially over features such as seamounts, banks, and ridges that are associated with short wavelength (<25 km wavelength) bathymetric and gravimetric features beyond that is recoverable in satellite‐derived data.
Exploring Sources of Uncertainty in Steric Sea‐Level Change Estimates
Authors: Camargo Carolina M. L. , Riva Riccardo E. M. , Hermans Tim H. J. , Slangen Aimée B. A. 
Published: September 2020

AbstractRecent studies disagree about the contribution of variations in temperature and salinity of the oceans—steric change—to the observed sea‐level change. This article explores two sources of uncertainty to both global mean and regional steric sea‐level trends. First, we analyze the influence of different temperature and salinity data sets on the estimated steric sea‐level change. Next, we investigate the impact of different stochastic noise models on the estimation of trends and their uncertainties. By varying both the data sets and noise models, the global mean steric sea‐level trend and uncertainty can vary from 0.69 to 2.40 and 0.02 to 1.56 mm/year, respectively, for 1993–2017. This range is even larger on regional scales, reaching up to 30 mm/year. Our results show that a first‐order autoregressive model is the most appropriate choice to describe the residual behavior of the ensemble mean of all data sets for the global mean steric sea‐level change over the last 25 years, which consequently leads to the most representative uncertainty. Using the ensemble mean and the first‐order autoregressive noise model, we find a global mean steric sea‐level change of 1.36 ± 0.10 mm/year for 1993–2017 and 1.08 ± 0.07 mm/year for 2005–2015. Regionally, a combination of different noise models is the best descriptor of the steric sea‐level change and its uncertainty. The spatial coherence in the noise model preference indicates clusters that may be best suited to investigate the regional sea‐level budget.
Robust Acceleration of Stratospheric Moistening and Its Radiative Feedback Under Greenhouse Warming
Authors: Xia Yan , Huang Yi , Hu Yongyun 
Published: September 2020

AbstractStratospheric water vapor (SWV) changes, in response to increasing CO2, as a feedback component may play an important role in the Earth's energy budget. It has drawn extensive studies in the past decade. Here, we calculate the SWV climate feedback using the 150‐year CO2 forcing (1pctCO2) simulations in the CMIP6 ensemble of models. All models robustly show a moistening of the stratosphere, causing a positive radiative feedback to surface warming. We find that the stratospheric moistening rate and the SWV feedback both increase with surface warming. The moistening occurs at a rate of 0.9 ± 0.1 ppmv K−1 and its radiative feedback measured by the fixed dynamical heating method is 0.11 ± 0.02 W m−2 K−1 in the first 50 model years; the moistening rate increases to 1.2 ± 0.2 ppmv K−1 and the feedback increases to 0.16 ± 0.03 W m−2 K−1 in the last 50 model years when the global‐mean surface temperature is 3.3 K warmer. These increases are found to be caused by an amplified rate of tropical tropopause warming with respect to surface warming, which is 0.6 and 1.1 K K−1 for the two 50‐year periods, respectively. We conclude that the SWV feedback is strengthening with surface warming, which can contribute to increasing climate sensitivity in the future under global warming.
Production and Transport of Supraglacial Debris: Insights From Cosmogenic 10Be and Numerical Modeling, Chhota Shigri Glacier, Indian Himalaya
Authors: Scherler D. , Egholm D. L. 
Published: September 2020

AbstractMany mountain glaciers carry some amount of rocky debris on them, which modifies surface ablation rates. The debris is typically derived from erosion of the surrounding topography and its supraglacial extent is predominantly controlled by the relative accumulation rates of debris versus snow. Because Global Warming results in shrinking glaciers as well as thawing permafrost worldwide, changes in both rates will most likely affect the evolution of supraglacial debris cover and thus the response of glaciers to climate change. Here we report 10Be concentrations measured in five amalgamated debris samples collected from the main medial moraine of the Chhota Shigri Glacier, India. Results suggest headwall erosion rates that are ~0.5–1 mm year−1, and apparently increasing (10Be concentrations are decreasing) toward the present. We employed a numerical ice flow model that we combined with a new Lagrangian particle tracing routine to explore the impact of spatial and temporal variability in erosion rates and source areas on 10Be concentrations in the medial moraine. Our modeling results show that neither changes in source areas, related to the transient response of the glacier to ongoing climate change, nor four different scenarios of spatial and temporal variability in erosion rates could explain the observed trend in 10Be concentrations. Although not accounted for in our modeling explicitly, we suggest that the observed trend could be due to transiently enhanced erosion of recently deglaciated areas, or to greater spatial variability in erosion rates than explored in our models.
Deflating the LLSVPs: Bundles of Mantle Thermochemical Plumes Rather Than Thick Stagnant “Piles”
Authors: Davaille Anne , Romanowicz Barbara 
Published: September 2020

AbstractBased on SEMUCB‐WM1 tomographic model, validated by other recent models, and fluid mechanics constraints, we show that the large low shear velocity provinces (LLSVPs) present at the base of the Earth's mantle beneath the Pacific and Africa do not extend as compact, uniform structures very high above the core‐mantle boundary. In contrast, they contain a number of well‐separated, low‐velocity conduits that extend vertically throughout most of the lower mantle. The conceptual model of compact piles, continuously covering the areal extent of the LLSVPs, is therefore not correct. Instead, each LLSVP is composed of a bundle of thermochemical upwellings probably enriched in denser than average material. It is only when the tomographic model is filtered to long wavelengths that the two bundles of plumes appear as uniform provinces. Furthermore, the overall shape of the LLSVPs is probably controlled by the distribution of subducted slabs, and due to their thermochemical nature, the position of both LLSVPs and individual upwelling dynamics should be time dependent. There is also evidence for smaller plumes originating near the CMB in the faster than average regions of the voting map of Lekic et al. (2012, https://doi.org/10.1016/j.epsl.2012.09.014) as well as other, barely resolved, weaker plumes within the LLSVPs. These finer‐scale features are starting to be resolved tomographically owing to improvements in full waveform modeling of body waves, including diffracted S waves (Sdiff) and waves multiply reflected on the core‐mantle boundary (ScS) and their codas.
Characterization and Quantification of Pore Water in Clays During Drying Process With Low‐Field NMR
Authors: Tian H. H. , Wei C. F. 
Published: September 2020

AbstractWater transport in large‐specific surface soil is controlled by soil microstructure and soil‐water interaction. In this paper, soil‐water interaction and confined water dynamics as well as soil microstructure are studied by combining the nuclear magnetic resonance technique and the mercury intrusion porosimetry. It is revealed that during a drying process pore water drainage occurs sequentially from larger pores to smaller pores, and surface interaction parameter ρ1 appears to be a well‐defined quantity at a water content above one water layer, below which ρ1 shows a different trend. With the two‐dimensional T1‐T2 correlation measurements, surface dynamical parameters, including residence time and surface affinity coefficient, are determined, showing that the mobility of pore water decreases gradually with the decrease in water potential. The effect of temperature on the soil‐water interaction is discussed via the variation of relaxation time with temperature. The increase in residence time and surface affinity coefficient as well as effective activation energy ΔE indicates that the mobility of pore water decreases with the decrease in water potential. In addition, the positiveness of ΔE indicates that unsaturated hydraulic conductivity of clay increases with temperature, and a larger ΔE implies that the unsaturated hydraulic conductivity for the sample equilibrated at smaller potential is more sensitive to the temperature. The average pore sizes of the saturated samples are also determined by the mercury intrusion porosimetry, showing clear consistency between the mercury intrusion porosimetry (MIP) and nuclear magnetic resonance (NMR) measurements.
Bone marrow mesenchymal stem cells-derived exosomal microRNA-193a reduces cisplatin resistance of non-small cell lung cancer cells via targeting LRRC1
Authors: Wu Hongbo , Mu Xiaoqian , Liu Lei , Wu Huijuan , Hu Xiufeng , Chen Lijuan , Liu Jie , Mu Yu , Yuan Fangfang , Liu Wenjing , Zhao Yanqiu 
Published: September 2020

AbstractExosomes are small endogenous membrane vesicles that can mediate cell communication by transferring genetic materials. Based on that, exosomes have always been discussed as a cargo carrier for microRNA (miRNA) transportation. Accumulating data have reported the inhibitory effects of microRNA-193a (miR-193a) on non-small cell lung cancer (NSCLC) cell progression. However, the mechanisms of miR-193a delivery to cancer cells and miR-193a in exosomes have not been explored clearly in NSCLC. Given that, this work aims to decode exosomal miR-193a in cisplatin (DDP) resistance of NSCLC cells. A549 and H1299 cell lines were screened out and their parent cells and drug-resistant cells were co-cultured with human bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (BMSC-Exo) that had been transfected with miR-193a mimic or si-LRRC1 to detect the colony formation, migration, apoptosis, invasion and proliferation of NSCLC cells. In vivo experiment was conducted to verify the in vitro results. BMSC-Exo with upregulated miR-193a and downregulated LRRC1 suppressed colony formation, invasion, proliferation and migration as well as advanced apoptosis of NSCLC parent cells and drug-resistant cells. BMSC-Exo combined with upregulated miR-193a reduced tumor volume and weight in mice with NSCLC. Functional studies report that BMSC-Exo shuffle miR-193a to suppress the colony formation, invasion, migration, and proliferation as well as advance apoptosis of NSCLC DDP-resistant cells via downregulating LRRC1.