bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual-band ambient energy harvesting systems based on metamaterials for self-powered indoorwireless sensor nodes
Authors: Le Minh Thuy , Ngo Van Duc , Nguyen Thanh Tung , Nguyen Quoc Cuong 
Published: December 2021

AbstractIn this study, we present a comprehensive dual-band ambient radio-frequency (RF) energy harvesting system, consisting of rectenna and power management circuit, to harvest energy from 2.45 and 5.8 GHz Wi-Fi. The rectenna employs a metamaterial antenna based on a split-ring resonator, which possesses omni-directional radiation pattern at both frequencies and compact size (0.18λ × 0.25λ at 2.45 GHz). The dual-band rectifier yields the highest efficiency of 42% at 2.45 GHz and 1 dBm input power, 30% at 5.8 GHz and − 7 dBm input power. The maximum RF-DC efficiency for each band is 72% at − 5 dBm and 27% at − 2 dBm, respectively. The power management circuit, consisting of a storing capacitor and a boost converter, is integrated to produce a stable, sufficient output voltage. The energy harvesting system, with its comprehensiveness, is suitable for supplying low-power wireless sensor nodes for indoor applications.
Risk of Heat‐Related Mortality, Disease, Accident, and Injury Among Korean Workers: A National Representative Study From 2002 to 2015
Authors: Yoon Jin‐Ha , Lee Won‐Tae , Yoon Min Joo , Lee Wanhyung 
Published: December 2021

AbstractMany studies have shown that heat waves can cause both death and disease. Considering the adverse health effects of heat waves on vulnerable groups, this study highlights their impact on workers. The present study thus investigated the association between heat exposure and the likelihood of hospitalization and death, and further identified the risk of heat‐related diseases or death according to types of heat and dose‐response modeling with heat threshold. Workers were selected from the Korean National Health Insurance Service‐National Sample Cohort 2002–2015, and regional data measured by the Korea Meteorological Administration were used for weather information. The relationship between hospitalization attributable to disease and weather variables was analyzed by applying a generalized additional model. Using the Akaike information criterion, we selected a model that presented the optimal threshold. Maximum daily temperature (MaxT) was associated with an increased risk of death and outdoor mortality. The association between death outdoors and MaxT had a threshold of 31.2°C with a day zero lag effect. History of medical facility visits due to the health effects of heat waves was evident in certain infectious and parasitic diseases (A and B), cardio and cerebrovascular diseases (I20–25 and I60–69), injury, poisoning, and other consequences of external causes (S, T). The study demonstrated that heat exposure is a risk factor for death and infectious, cardio‐cerebrovascular, and genitourinary diseases, as well as injuries or accidents among workers. The finding that heat exposure affects workers' health has future implications for decision makers and researchers.
CMIP6 Models Underestimate the Holton‐Tan Effect
Authors: Elsbury Dillon , Peings Yannick , Magnusdottir Gudrun 
Published: December 2021

AbstractThe teleconnection between the Quasi‐Biennial Oscillation (QBO) and the Arctic polar vortex is investigated using Coupled Model Intercomparison Project 6 (CMIP6) models. Output from 14 CMIP6 models is compared with reanalysis, three experiments with prescribed QBOs, one of which has no free polar stratospheric variability, and transient experiments in which a QBO is prescribed in runs previously devoid of a QBO. Each CMIP6 model underestimates the Holton‐Tan effect (HTE), the weakening of the polar vortex expected with QBO easterlies in the tropical lower stratosphere. To establish why, potential vorticity maps are used to investigate longitudinal variations in the teleconnection. Prescribing easterly QBO in the transient experiments promotes more high‐latitude planetary wave breaking by influencing the mid‐latitude stratospheric circulation, particularly over Asia. CMIP6 models that better simulate this response over Asia better simulate the HTE. These models also have stronger 10 hPa QBO westerlies.
Observation and Fully Thermal Simulation of Quasi‐Electrostatic Magnetosonic Waves
Authors: Gao Zhonglei , Liu Si , Xiao Fuliang , Zhou Qinghua , He Qian , Li Tong , Shang Xiongjun , Yang Chang , Zhang Sai , Yang Qiwu 
Published: December 2021

AbstractMagnetosonic (MS) waves are generally considered as electromagnetic harmonic fluctuations below the lower hybrid frequency. Here we present a correlated observation of proton ring‐like distribution and low harmonic magnetosonic waves with undetectable magnetic components (called QEMS). We conduct fully thermal simulations (WHAMP) to investigate the wave properties. The calculated growth rates can reproduce the observed spectral characteristics and demonstrate that the QEMS waves are excited as ion Bernstein modes by proton ring‐like distribution. The ratios between the wave electric and magnetic amplitudes E/B given by WHAMP indicate that the magnetic spectral densities are below the instrument noise level, and the ratios are ∼7–80 times larger than the wave phase speeds Vph, suggesting that the QEMS waves are essentially quasi‐electrostatic, not just visually quasi‐electrostatic due to the measurement limit. This study provides further insights into the QEMS natures.
Ongoing Drainage Reorganization Driven by Rapid Lake Growths on the Tibetan Plateau
Authors: Liu Kai , Ke Linghong , Wang Jida , Jiang Ling , Richards Keith S. , Sheng Yongwei , Zhu Yunqiang , Fan Chenyu , Zhan Pengfei , Luo Shuangxiao , Cheng Jian , Chen Tan , Ma Ronghua , Liang Qiuhua , Madson Austin , Song Chunqiao 
Published: December 2021

AbstractDrainage reorganization generally occurs on geological time scales under unstable river network conditions. A few local‐scale studies indicate that recent climatic changes might accelerate the drainage reorganization process. However, large‐scale drainage reorganization during the modern era is rarely documented. This study examines ongoing drainage reorganization on the endorheic Tibetan Plateau (TP) as a primary result of drastic lake expansion. A total of 11 drainage system reorganization events comprising 24 different lake basins and covering a total area of 61,115 km2 occurred between 2000 and 2018. Assuming the continued growth rate of TP lakes, we project another 20 basins will be reorganized before 2030. These drainage basin reorganizations not only alter hydrological processes in the endorheic TP but may also cause the endorheic‐exorheic transition, leading to the upstream sprawl of the Yangtze River Basin and posing outburst flooding risks on China's key infrastructure such as the Qinghai‐Tibet Railway.
An Approach to Empirical Mapping of Incoherent Internal Tides With Altimetry Data
Authors: Egbert G. D. , Erofeeva S. Y. 
Published: December 2021

AbstractMuch of the internal tide (IT) is coherent with tidal forcing, but interactions with time‐varying ocean flows result in an incoherent component of IT (IIT), which will complicate interpretation of data from the upcoming Surface Water Ocean Topography (SWOT) mission. Here, we demonstrate a simple scheme for estimation of these IIT. We use a short‐time harmonic analysis of outputs of a wind‐ and tidally forced ocean model to generate an ensemble of IT variations in an ocean patch. Principal Components Analysis is used to define the dominant spatial patterns, and combined with sinusoidal time variations at tidal frequencies to define spatio‐temporal basis functions that are used to fit sparse altimetry data available in short time windows. The scheme is illustrated using a 1‐yr Hybrid Coordinate Ocean Model (HYCOM) run off the Amazon Shelf. Tests with synthetic (SWOT) and real (nadir altimetry) data demonstrate that a significant fraction of IIT can be recovered with this procedure.
Finite‐Size Analysis of the Collapse of Dry Granular Columns
Authors: Man Teng , Huppert Herbert E. , Li Ling , Galindo‐Torres Sergio A. 
Published: December 2021

AbstractIn this letter, we focus on the size effect of granular column collapses, which are potentially connected to the dynamics of complex geophysical flows, even if the link between microscopic structures of granular assemblies and their macroscopic behaviors is still not well understood. Using the spheropolyhedral discrete element method (DEM), we show that the column radius/grain size ratio has a strong influence on the collapse behavior. A finite‐size analysis, which is inspired by a phase transition around an inflection point, is performed to obtain a general scaling equation with critical exponents for runout distances. We further link the size effect with the strong force network and formalize a correlation length scale that exponentially scales with the effective aspect ratio. Such a scaling solution shows similarities with the percolation problem of two‐dimensional random networks and can be extended to other similar natural and engineering systems.
The Mechanisms of Cloudiness Evolution Responsible for Equilibrium Climate Sensitivity in Climate Model INM‐CM4‐8
Authors: Volodin E. 
Published: December 2021

AbstractCurrent climate models demonstrate large discrepancy in equilibrium climate sensitivity (ECS). The effects of cloudiness parameterization changes on the ECS of the INM‐CM4‐8 climate model were investigated. This model shows the lowest ECS among CMIP6 models. Reasonable changes in the parameterization of the degree of cloudiness yielded ECS variability of 1.8–4.1 K in INM‐CM4‐8, which was more than half of the interval for the CMIP6 models. The three principal mechanisms responsible for the increased ECS were increased cloudiness dissipation in warmer climates due to the increased water vapor deficit in the non‐cloud fraction of a cell, decreased cloudiness generation in the atmospheric boundary layer in warm climates, and the instantaneous cloud response to CO2 increases due to stratification changes.
Meridional Migration of ENSO Impact on Tropical Atlantic Precipitation Controlled by the Seasonal Cycle
Authors: Jiang Feng , Zhang Wenjun , Jin Fei‐Fei , Stuecker Malte F. 
Published: December 2021

AbstractPrevious studies suggest that the El Niño–Southern Oscillation (ENSO) impact on tropical Atlantic climate variability shows strong seasonal preference, manifesting itself primarily in the decaying boreal spring season. However, here we show that a robust ENSO signal in tropical Atlantic precipitation anomalies can be detected throughout ENSO’s whole lifecycle. We find that the ENSO impact on the tropical Atlantic precipitation migrates meridionally, following the seasonal migration of the Atlantic Intertropical Convergence Zone (ITCZ). Taking into account the modulation of the local seasonal cycle, the full spatiotemporal characteristics of ENSO’s impact on tropical Atlantic precipitation are uncovered. Furthermore, we demonstrate that climate models can simulate the modulation of ENSO‐related precipitation over the tropical Atlantic by the local seasonal cycle despite the substantial mean state model bias in the Atlantic ITCZ. This extended perspective on ENSO’s impact on tropical Atlantic climate variability enhances prospects for skillful year‐round regional climate prediction.
Propagation of Chorus Waves Generated in Minimum‐B Pockets
Authors: Kang Ning , Bortnik Jacob , An Xin , Claudepierre Seth G. 
Published: December 2021

AbstractWe present the first ray tracing results of chorus waves generated in minimum‐B pockets. A new ray tracer is developed to accommodate an arbitrary magnetic field model, which enables us to construct minimum‐B pocket geometries using the Tsyganenko (1989) model. Rays with different frequencies and initial wave normal angles are launched from minimum‐B pockets and traced under different geomagnetic activity and hot electron density conditions. Our results indicate that chorus waves generated from minimum‐B pockets are usually highly localized and thus are unlikely to be detected unless the spacecraft is very close to the source region. These waves are also very unlikely to propagate into the plasmasphere. The propagation distances generally decrease with increasing geomagnetic activity.
Crystallographic Preferred Orientation (CPO) Development Governs Strain Weakening in Ice: Insights From High‐Temperature Deformation Experiments
Authors: Fan Sheng , Cross Andrew J. , Prior David J. , Goldsby David L. , Hager Travis F. , Negrini Marianne , Qi Chao 
Published: December 2021

AbstractStrain weakening leads to the formation of high‐strain shear zones and strongly influences terrestrial ice discharge. In glacial flow models, strain weakening is assumed to arise from the alignment of weak basal planes—the development of a crystallographic preferred orientation, CPO—during flow. However, in experiments, ice strain weakening also coincides with grain size reduction, which has been invoked as a weakening mechanism in other minerals. To interrogate the relative contributions of CPO development and grain size reduction toward ice strain weakening, we deformed initially isotropic polycrystalline ice samples to progressively higher strains between −4 and −30°C. Microstructural measurements were subsequently combined with flow laws to separately model the mechanical response expected to arise from CPO development and grain size reduction. Magnitudes of strain weakening predicted by the constitutive flow laws were then compared with the experimental measurements. Flow laws that only consider grain size do not predict weakening with strain despite grain size reduction. In contrast, flow laws solely considering CPO effects can reproduce the measured strain weakening. Thus, it is reasonable to assume that strain weakening in ice is dominated by CPO development, at least under high temperature ( ≥ 0.9) and high stress (>1 MPa), like those in our experiments. We speculate that at high homologous temperatures ( ≥ 0.9), CPO development will also govern the strain weakening behavior of other viscously anisotropic minerals, like olivine and quartz. Overall, we emphasize that geodynamic and glaciological models should incorporate CPOs to account for strain weakening, especially at high homologous temperatures.
Modeling the Morphodynamic Response of Estuarine Intertidal Shoals to Sea‐Level Rise
Authors: Elmilady H. , van der Wegen M. , Roelvink D. , van der Spek A. 
Published: December 2021

AbstractIntertidal shoals are key features of estuarine environments worldwide. Climate change poses questions regarding the sustainability of intertidal areas under sea‐level rise (SLR). Our work investigates the SLR impact on the long‐term morphological evolution of unvegetated intertidal sandy shoals in a constrained channel‐shoal system. Utilizing a process‐based model (Delft3D), we schematize a short tidal system in a rectangular (2.5 × 20 km) basin with a high‐resolution grid. An initial, mildly sloping, bathymetry is subjected to constant semidiurnal tidal forcing, sediment supply, and small wind‐generated waves modeled by SWAN. A positive morphodynamic feedback between hydrodynamics, sediment transport, and morphology causes the emergence of large‐scale channel‐shoal patterns. Over centuries, tide‐residual sediment transport gradually decreases leading to a state of low morphological activity balanced by tides, waves, and sediment supply. Tidal currents are the main driver of the SLR morphodynamic adaptation. Wave action leads to wider and lower shoals but does not fundamentally change the long‐term morphological evolution. SLR causes increased flood dominance which triggers sediment import into the system. Shoals accrete in response to SLR with a lag that increases as SLR accelerates, eventually causing intertidal shoals to drown. Seaward shoals near the open boundary sediment source have higher accretion rates compared to landward shoals. Similarly, on a shoal‐scale, the highest accretion rates occur at the shoal edges bounding the sediment suppling channels. A larger sediment supply enhances the SLR adaptation. Waves help distribute sediment supplied from channels across shoals. Adding mud fractions leads to faster, more uniform, accretion and muddier shoals under SLR.
Identification of Debris‐Flow Channels Using High‐Resolution Topographic Data: A Case Study in the Quebrada del Toro, NW Argentina
Authors: Mueting A. , Bookhagen B. , Strecker M. R. 
Published: December 2021

AbstractResolving Earth's surface at the meter scale is essential for an improved understanding of the dynamics of mass‐movement processes. In this study, we explore the applicability and potential of digital elevation models (DEMs) derived from stereophotogrammetry to detect debris‐flow channels in the Quebrada del Toro in the northwestern Argentine Andes. Our analysis relies on a high‐resolution (3 m) DEM created from SPOT‐7 tri‐stereo satellite data. We carefully validated DEM quality with ∼6,000 differential GPS points and identified optimal parameters for DEM generation in high‐relief terrain. After multiple processing steps, we achieved an accuracy of 0.051 ± 1.915 m (1σ) using n = 3,139 control points with cm precision. Previous studies have used the drainage area and slope framework to identify topographic signatures of debris flows within a catchment. We built upon this and investigated individual river‐channel segments using connected‐component (CC) analysis on meter‐scale topographic data. We define CC as segments of similar slope along the channel profile. Based on seven manually identified debris‐flow catchments, we developed a debris‐flow similarity index using component length and mean channel‐segment slope and identified channel segments that have likely been shaped by debris flows. The presented approach has the potential to resolve intra‐catchment variability of transport processes, allows to constrain the extent of debris‐flow channels more precisely than slope‐area analysis, and highlights the versatility of combined space‐ and field‐based observations for natural‐hazard assessments.
Seasonal Changes of Organic Carbon Mixing, Degradation and Deposition in Yangtze River Dominated Margin Related to Intrinsic Molecular and External Environmental Factors
Authors: Han Lulu , Wang Yinghui , Xiao Wenjie , Wu Jianqiang , Guo Lixia , Wang Yasong , Ge Huangmin , Xu Yunping 
Published: December 2021

AbstractThe East Asian monsoon is characterized by warm, humid summer and cool, dry winter that results in seasonal changes in fluvial sediment and organic carbon (OC) discharge. Here, we report measurements of elemental, isotopic, and optical compositions of OC in surface waters and sediments that were collected along the lower Yangtze River, Estuary, and East China Sea continuum in March and July 2019. The principal component analysis separates samples into three groups that correspond to fresh water area, mixing area, and seawater area. The terrigenous signal in the mixing area, indicated by water salinity and δ13C, is stronger in July. The applications of binary mixing models based on water salinity, dissolved OC (DOC) concentration and specific terrigenous fluorescence component suggest: (a) net removal of DOC from waters in July, but net addition of DOC into waters in March, attributed to more extensive degradation and larger deposition of OC in summer; and (b) more conservative behaviors of terrigenous OC compared to marine or mixed OC, suggesting an important role of intrinsic molecular characteristics on the persistence of DOC. The estimated monthly OC burial flux in the estuary and continent shelf is 0.48 × 1012 g in July and 0.081 × 1012 g of OC in March, equal to 15.5% and 2.6% of the annual OC discharge by the Yangtze River, respectively. Our study suggests that the burial of OC mainly occurs in the summer monsoon due to the larger sediment load of the Yangtze River, prevailing southeastern wind, and intensified Kuroshio Current.
Sensitivity of Convection Permitting Simulations to Lateral Boundary Conditions in Idealized Experiments
Authors: Ahrens Bodo , Leps Nora 
Published: December 2021

AbstractLimited‐area convection‐permitting climate models (CPMs) with horizontal grid‐spacing less than 4 km and not relying on deep convection parameterisations (CPs) are being used more and more frequently. CPMs represent small‐scale features such as deep convection more realistically than coarser regional climate models (RCMs) with deep CPs. Because of computational costs, CPMs tend to use smaller horizontal domains than RCMs. As all limited‐area models (LAMs), CPMs suffer issues with lateral boundary conditions (LBCs) and nesting. We investigated these issues using idealized Big‐Brother (BB) experiments with the LAM COSMO‐CLM. Grid‐spacing of the reference BB simulation was 2.4 km. Deep convection was triggered by idealized hills with driving data from simulations with different spatial resolutions, with/without deep CP, and with different nesting frequencies and LBC formulations. All our nested idealized 2.4‐km Little‐Brother (LB) experiments performed worse than a coarser CPM simulation (4.9 km) which used a four times larger computational domain and yet spent only half the computational cost. A boundary zone of grid‐points of the LBs could not be interpreted meteorologically because of spin‐up of convection and boundary inconsistencies. Hosts with grid‐spacing in the so‐called gray zone of convection (ca. 4–20 km) were not advantageous to the LB performance. The LB's performance was insensitive to the applied LBC formulation and updating (if ‐hourly). Therefore, our idealized experiments suggested to opt for a larger domain instead of a higher resolution even if coarser than usual ( km) as a compromise between the harmful boundary problems, computational cost and improved representation of processes by CPMs.
Ecosystem Photosynthesis in Land‐Surface Models: A First‐Principles Approach Incorporating Acclimation
Authors: Mengoli Giulia , Agustí‐Panareda Anna , Boussetta Souhail , Harrison Sandy P. , Trotta Carlo , Prentice I. Colin 
Published: December 2021

AbstractVegetation regulates land‐atmosphere, water, and energy exchanges and is an essential component of land‐surface models (LSMs). However, LSMs have been handicapped by assumptions that equate acclimated photosynthetic responses to the environment with the fast responses observable in the laboratory. The effects of acclimation can be taken into account by including PFT‐specific values of photosynthetic parameters, but at the cost of increasing parameter requirements. Here, we develop an alternative approach for including acclimation in LSMs by adopting the P model, an existing light‐use efficiency model for gross primary production (GPP) that implicitly predicts the acclimation of photosynthetic parameters on a weekly to monthly timescale via optimality principles. We demonstrate that it is possible to explicitly separate the fast and slow photosynthetic responses to environmental conditions, allowing the simulation of GPP at the sub‐daily timesteps required for coupling in an LSM. The resulting model reproduces the diurnal cycles of GPP recorded by eddy‐covariance flux towers in a temperate grassland and boreal, temperate and tropical forests. The best performance is achieved when biochemical capacities are adjusted to match recent midday conditions. Comparison between this model and the operational LSM in the European Centre for Medium‐range Weather Forecasts climate model shows that the new model has better predictive power in most of the sites and years analyzed, particularly in summer and autumn. Our analyses suggest a simple and parameter‐sparse method to include both instantaneous and acclimated responses within an LSM framework, with potential applications in weather, climate, and carbon‐cycle modeling.