bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection and Quantification of Micro(nano)plastics Release from Photolysis of Surgical Masks
Authors: Peng Guyu , Materic Dusan , Reemtsma Thorsten
Published: February 2023

Since the Covid-19 pandemic, 129 billion masks have been consumed each month worldwide. Fate of masks not only include waste disposal sites and natural environments, but masks made from synthetic fibers may release micro(nano)plastics (MNPLs) that may reach respiratory tracts. However, degradation rate of MNPLs generated from masks have been unknown.Here, we simulated the photolysis of surgical masks made from polypropylene equivalent to 900 days. Size-fractionated MNPL formation was quantified using vibrational spectroscopic imaging, and mask deformation and morphology were characterized with correlative microscopy. Three layers of masks did not exhibit signs of degradation from hydroxyl and carbonyl groups, however, the outer layer exhibited a linear increase in crystallinity calculated from the peak height of two characteristic bands, indicating that degradation started from amorphous regions. However, for microplastics > 10 μm, both groups were observed, and mass concentration was 10 mg/item calculated from FTIR imaging data. Fine microplastics <10 μm were imaged and fitted as ellipses, and the most abundant aspect ratio was 2. Nanoplastics (<1 μm) with an average size of 149 (59) nm were detected by SEM/STEM and Raman spectroscopy. Cluster analyses on spectra categorized three groups, suggesting different additives (e.g., dyes) were added. This study detected nanoplastics from degraded masks, which have major implications for their environmental fate and human health effects.
Simplified integrated modeling and potential groundwater management benefits of the unsaturated zone in the Urucuia aquifer system, Brazil
Authors: Klammler Harald , Araújo da Silva Leão Caio , Bastos Leal Luiz Rogério , Hatfield Kirk
Published: February 2023

An integrated perspective of the terrestrial part of the hydrological cycle from precipitation over soil and aquifer storage to river discharge is fundamental for a sound hydro(geo)logical understanding and, hence, a sustainable groundwater management. Simplified (or reduced-order) approaches can be an efficient tool to focus on the most relevant drivers, processes and responses of a system based on a parsimonious set of parameters and a relatively simple computational implementation. The Urucuia sandstone aquifer system in north-eastern Brazil is a high-plain region with mostly deep unconfined water tables and intensive groundwater pumping for agricultural irrigation causing social and political conflict. Here we develop a coupled reduced-order model of the high-plain and valley aquifer portions in the southern part (approximately 10000 km2) of the Urucuia aquifer, considering the soil zone (partitioning rainfall into evapotranspiration and deep percolation), thick vadose zones (up to approximately 100 m deep with unsaturated vertical moisture transport), and the saturated zone (generally over 100 m thick) providing river discharge. Data for model input (precipitation and potential evapotranspiration) and validation (river discharge) are obtained from the CAMELS-BR database as time series over approximately 40 years. Additional but shorter time series of groundwater levels in high-plain and valley regions are obtained from the RIMAS well database. We show that the much lower seasonality in water table fluctuations observed in the high-plain regions can be explained by the deeper unsaturated zone. While seasonality in river discharge may be attributed to the base flow from the valley aquifer portion, discharge recessions during the dry (practically zero rainfall) months of the year are sustained by the much larger aquifer portions underlying the high-plains. Groundwater pumping is considered as abstraction from storage in the saturated zone and its impact on groundwater levels and river discharges are evaluated with respect to climatic oscillations and long-term trends. The fact that the unsaturated moisture transport through the thick vadose zones under the extensive high-plains may take several years offers an interesting opportunity (in term of lead time) for groundwater management, if deep percolation leaving the soil zone is adequately estimated or measured over time.
Geophysical modelling of vertical motion processes constrained by geodetic and geological observations (UPLIFT)
Authors: Bunge Hans-Peter , Chen Yi-Wei , Friedrich Anke , Pail Roland ,   UPLIFT Team
Published: February 2023

Vertical motion of the Earth’s lithosphere (uplift) occurs on different spatial and temporal scales. Commonly assumed to be primarily related to plate tectonic mechanisms and isostatic adjustment, it has become clear that mantle related forcing and in particular mantle plumes are a significant contributor to uplift events in many regions of the world, making vertical motions a powerful probe into sublithospheric processes. Significant improvements of observational methods (e.g. satellite missions) and publicly-accessible databases (e.g. digital geological maps) make it now feasible to map vertical motions from geodetic to geologic time scales. This in turn provides invaluable constraints to inform key, yet uncertain, parameters (e.g. rheology) of geodynamic models. Such models also contribute powerful insight into complex landscape evolution processes at interregional to continental scales. Here we report on a new (starting date April 2022) Research Training Group (RTG) 2698, with 10 individual dissertation projects and a Post-doc project, funded by the German Research Foundation. An interdisciplinary approach of Geodynamics, Geodesy and Geology aims to answer questions related to how the interaction of exo- and endogenic forcing shapes a diverse array of earth processes from landscape evolution to the occurrence of earthquakes. The RTG uses a combined interpretation of interdisciplinary observations with different spatial and temporal sensitivity, in conjunction with physical models, to disentangle different uplift mechanisms, including the plume, plate and isostatic mode, based on their specific spatial and temporal patterns. We will give an overview on the key philosophy and main architecture of the RTG. Core components include an integrated geophysical process model, composed of an adjoint geodynamic model that accounts for seismic tomography and mineralogy, coupled with a landscape evolution model, with the lithosphere as a filter function, and targeted observations that include geodetic (geometric and gravimetry) data to reflect contemporary uplift processes combined with high precision, geological, magnetostratigraphic and geomorphologic data to reflect uplift processes and sedimentation rates on geological time scales. The modeling will be complemented by a thorough uncertainty analysis and an enhanced visualization of the key results.
Rupture Branching and Propagation at the Eastern End of the 2021 Mw 7.4 Madoi Earthquake, North Tibet Plateau
Authors: Yao Wenqian , Liu-Zeng Jing , Wang Zijun
Published: February 2023

The propagation of the 2021 Mw7.4 Madoi earthquake rupture from the central Jiangcuo fault (JCF) onto the eastern portion exhibits the most complex geometry with a series of conjugate faults, bends, and stepovers. At the east ~50 km of the 2021 epicenter, the surface rupture along the Jiangcuo eastern branch (JCEB) deviating ~12° anticlockwise from the general strike provides a valuable chance for understanding the particularly complex surface ruptures propagation and the branching behavior of the poorly known JCEB. Using sub-metric orthophotos collected by UAV with a ground resolution of 6 cm, complemented by multiple field investigations, we implemented the surface rupture mapping and coseismic slip distribution of the JCEB in detail associated with this earthquake sequence. Our mapping illuminated the sporadic breaks of the tectonic region in the dune area immediately near the branching point and eastward propagated linear rupture trace. The measurements of the high-resolution coseismic slip along the JCEB show that the slip distribution reveals an approximate dogtail shape to the eastern termination with the maximum left-lateral strike-slip offset of 2.9 m. These data might support the perspective that the rupture propagated with a supershear velocity toward the east. Combined with the accrued displacements along the JCEB, these results indicate that the poorly known divergent branch could accumulate pre-2021 surface breaks as an immature fault and bifurcated in the Madoi quake due to the matched regional stress field. We found linear surface breaks along the NW-strike geologic faults indicating triggered coseismic slip on conjugate faults. In the meantime, the intersections with conjugate faults mark discontinuities in rupture geometry and surface slip on the main fault, suggesting strong fault interaction in the eastern tip zone of the Madoi rupture.
Application of carbonate U-Pb geochronology in dating of diagenesis and hydrothermal activity
Authors: Lan Zhongwu , M W Roberts Nick , Wu Shitou , Wang Fangyue , Wang Hao , Cao Rong , Li Zhensheng , Zhou Ying , Shi Kaibo , Liu Bo
Published: February 2023

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb geochronology of calcite has been an emerging research direction in recent years that has been widely applied to various disciplines, such as dating of brittle deformation, biological biomineralization, oceanic crust alteration, and hydrocarbon migration. The method has the advantage of quickly locating regions of relatively high uranium content and radiogenic lead that avoids the time-consuming procedures traditionally required for isotope dilution methods. Herein, we show how this method is successfully applied to dating of diagenesis and hydrothermal activity in Precambrian-Phanerozoic sedimentary rocks, but with a note of caution that the susceptibility of the calcite U-Pb isotope system to fluid activities means interpretation of calcite U-Pb data and selection of calcite standard should be cautioned. We demonstrate the following case studies: LA-ICP-MS calcite U-Pb geochronology has aided in defining the Mesoproterozoic-Neoproterozoic boundary (ca. 1010 Ma) in North China Craton. It also constrains the timing of calcite infillings in the Ediacaran cap carbonate to be ca. 636 Ma, indicating an early diagenetic origin and thus confirming a methane seepage hypothesis. Two episodes of hydrothermal activity (ca. 290 Ma and ca. 250 Ma) have been recognized from the Cambrian carbonate in the Tarim region, which was induced by the Permian Tarim Large Igneous Province (LIP) and Indosinian orogeny, respectively.
residual space distribution law in long-wall old mining area
Authors: Guo Zhi , Lu Wei , Zhou Yongqiang , Zhang Meng , Liao Changlong , wang Changxiang
Published: February 2023

Grouting treatment in old goafs is an effective method to achieve sustainable development of mining areas after coal seam mining. Due to the concealment of the old goaf and the lack of historical information, it is difficult to directly obtain the distribution of the residual void in the old goaf. In this study, the residual void distribution law of the longwall old goaf area was studied through similar material simulation test, gangue compression test and stress arch theory. The results showed that the collapse zone can be divided into regular collapse zone and irregular collapse zone. Fissure zone and regular collapse zone have few grouting voids due to the closing effect. Due to the different forms of crushing, the irregular collapse zone has large voids and was difficult to completely close with the passage of time, which is the key area of grouting treatment. For the longwall old goaf area that has reached full mining, the stress relief zone was formed at both ends of the open-off cut and the stop-mining line, and the stress recovery zone and the stress stabilization zone were formed in turn close to the middle of the goaf area. The evolution process of stress arch and fracture arch in the stope can be divided into two stages and three periods. The first stage: the development stage of fracture arch and stress arch, that is, the stress relief and stress recovery period of broken gangue in the goaf. The second stage: the fracture arch and stress arch formation stage, that is, the stress stabilization period of broken gangue in the goaf area. On the basis of the above research, the concept of residual void equivalent height was proposed, and its calculation formula was given, and furthermore, the formula for the estimation of grouting volume was given. The height of the irregular collapse zone was 0.915~0.975 times of the coal seam mining thickness, the residual void equivalent height was about 0.3 times the mining thickness (take its upper limit value), and the residual void equivalent height in insufficiently collapsed area was 0.5 times the mining thickness.
Comparison of the Magnetic Field Inferred by SO/PHI-HRT and SDO/HMI
Authors: Sinjan Jonas , Calchetti Daniele , Hirzberger Johann , Solanki Sami Khan , del Toro Iniesta Jose Carlos , Woch Joachim , Gandorfer Achim , Alvarez-Herrero Alberto , Appourchaux Thierry , Volkmer Reiner , Orozco Suárez David
Published: February 2023

Onboard the Solar Orbiter spacecraft is the Polarimetric and Helioseismic Imager (SO/PHI), which has two telescopes, a high resolution telescope (HRT) and the full disk telescope (FDT). The instrument is designed to infer the photospheric magnetic field through differential imaging of the polarised light emitted from the Sun. It is the first magnetograph to move out of the Sun-Earth Line, providing excellent stereoscopic opportunities with other ground and space based instruments. Of particular interest is the comparison between SO/PHI-HRT and the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO/HMI). They probe the same magnetically sensitive line of Fe1: 6173 Å and have the same aperture diameter. In March 2022 Solar Orbiter crossed the Sun-Earth line, providing an excellent opportunity for a comparison. Here a comparison between the magnetic fields, both line-of-sight and all three vector components, inferred by SDO/HMI and SO/PHI-HRT during the conjunction, are presented. 
Interaction between tectonics and climate encoded in the planform geometry of stream networks on the eastern Tibetan Plateau
Authors: Li Minhui , Seybold Hansjörg , Wu Baosheng , Chen Yi , Kirchner James W.
Published: February 2023

Stream networks are highly abundant across Earth’s surface, reflecting the tectonic and climatic history under which they have developed. Prior studies suggest that stream branching angles are strongly correlated with climatic aridity, with a tendency toward wider branching angles in more humid climates. However, branching angles are also shaped by topography and thus by tectonic forcing. The importance of climate relative to tectonics, especially in tectonically active regions, remains ambiguous. Here we evaluate the relative dominance of climatic aridity and channel slope in shaping the branching angles of stream networks on the eastern Tibetan Plateau, a region with complex tectonics, variable climate, and diverse landscapes. Climatic aridity and channel slopes vary systematically from the relatively flat, dry interior to the steep, wet margin. Our analysis shows that the correlation between branching angles and climatic aridity reverses between the relatively flat interior and the steep eastern margin and the shift is observed in the transitional zone at intermediate topographic slopes. In the flat interior, branching angles are wider in wetter climates, consistent with previous studies in other regions. As one approaches the Tibetan Plateau’s eastern margin, however, branching angles become narrower as climate becomes wetter and topographic gradients simultaneously become steeper. These general patterns also persist after removing side-branches. These results indicate that climatic controls on branching angles are gradually overwhelmed by tectonic controls as one goes from the relatively flat terrain of the interior to the steeper terrain of the tectonically active eastern margin. Our findings demonstrate the joint influence of tectonic forcing and climate in shaping river network morphology.
Water-Energy-Food Nexus Analysis at Basin Level to Improve the Resources Availability and Accessibility Sources
Authors: Mondal Krishna , Chatterjee Chandranath , Singh Rajendra
Published: February 2023

Water, Energy and Food (WEF) are considered global security, prosperity, and equity pillars. These resources are fundamentally linked: food production requires both water and energy; pumping, treating, and transporting water requires energy; energy production requires water, which faces numerous challenges, including growing population density, rapid urbanisation, economic growth, poverty, hunger, changing diet habits and climate changes. In this study, we have developed a spatially distributed (block-scale) WEF-Nexus model with the help of the Modified Pardee-RAND Water-Energy-Food Security Index (MPRWEFSI) equation to meet the basin-scale WEF challenges. The Pardee RAND WEF security index has been modified by considering the industrial and agricultural water requirement, renewal energy and water sources, modern farm equipment uses, hunger index, etc. The developed model can produce the resources availability, accessibility and security indexes. We have tested the model in the Kangsabati river basin for 2011. The estimated values of the water, energy, and food subindex reveals that the Jaypur block (1.0) had the highest water security, the Bipur-II block (0.865) had the highest energy security, and the Jhargram block (1.0) had the highest food security. Conversely, the Jhalda-II block (0.65) has the lowest water security, the Kharagpur-I block (0.52) has the lowest water security, and the Purulia-I block (0.56) has the lowest water security. Furthermore, Jaypur (0.92) and Jhalda-II (0.63) had the highest and lowest overall WEF nexus index. The result also shows that the basin's water, energy, and food availability indexes are 0.88, 0.91 and 0.65, accessibility indexes are 0.92, 0.60, and 0.98, and security indexes are 0.89, 0.73 and 0.79, respectively. The overall WEF nexus Index of the basin is 0.80. Although the availability and accessibility of resources are in a considerable range, different schemes and policies are needed to achieve a hundred per cent resources availability, security, and security. Likewise, basin-scale WEF management will ensure better management of WEF resources holistically and equitably. This study will be helpful in influencing the policy and resource planning process.Keywords: Resources Availability, WEF-Nexus, Pardee RAND, Basin-scale 
Exploring the climatic and non-climatic fingerprints of the hydrogen isotope signals in tree rings.
Authors: Vitali Valentina , Peters Richard , Lehmann Marco , Leuenberger Markus , Treydte Kerstin , Büntgen Ulf , Schuler Philipp , Saurer Matthias
Published: February 2023

The analysis of a Europe-wide network of tree-ring stable isotopes has shown that the climatic signal of δ2H in tree-ring cellulose (C6H10O5), is far weaker compared to those recorded in carbon (δ13C) and oxygen (δ18O)isotopes. Furthermore, the δ2H and δ18O relationships were shown to be site dependent and significantly deviated from the Global Meteoric Water Line. These results suggest that non-climatic effects are modifying the hydrological signature of δ2H. Recent experiments have underlined the potential of δ2H in tree-ring cellulose as a physiological indicator of shifts in autotrophic versus heterotrophic processes. However, the impact of these processes has not yet been quantified under natural conditions.Defoliating insect outbreaks can disrupt photosynthetic production and carbon allocation, stimulating the remobilization of stored carbohydrates. Such disturbance events, therefore, provide unique opportunities to evaluate the impact of changes in the use of fresh versus stored non-structural carbohydrates, i.e., of non-climatic signals stored in δ2H. By exploring a 700-year tree-ring record from Switzerland, we assess the impact of 79 larch budmoth (LBM, Zeiraphera griseana) outbreaks on the growth of its Larix decidua host trees.LBM outbreaks significantly altered the tree-ring isotopic signature, creating a 2H-enrichment and a depletion in 18O 13C. Changes in tree physiology during outbreak years are shown by the decoupling of δ2H and δ18O (O–H relationship), in contrast to the positive correlation in non-outbreak years. The O–H relationship in outbreak years was not significantly affected by temperature, indicating that non-climatic physiological processes dominate over climate in determining δ2H variations. We conclude that the combination of these isotopic parameters may serve as a metric for assessing changes in physiological mechanisms over time and that hydrogen isotopes can be considered as a proxy for non-climatic disturbance signals in dendrochronological research.
Competitive CH4 bubble growth in aquatic muds
Authors: Katsman Regina , Zhou Xiongjie
Published: February 2023

Methane (CH4) bubbles residing in shallow aquatic muds pose a significant threat to the environment. Impeded by the muddy sediment opacity and insufficient resolution for their characterization, past studies overlooked bubble interactions during their growth. The competitive growth of CH4 bubble pairs with different initial sizes is simulated, using a mechanical/reaction-transport numerical model. Mechanical and solute transport interactions were found to dominate at the different stages of the bubble growth, both retarding the smaller competitive bubble growth. Stress from the large competitive bubble affects the inner pressure and diffusive flux to the smaller bubble, producing its slower initial growth. The large competitive bubble diverts CH4 from the smaller one at the later stages, thus inhibiting its growth even more. Bubble stress interactions may produce more laterally oriented smaller bubbles and significant deformations of the larger ones. Competitive bubble growth may shape a bubble size distribution pattern, promote muddy sediment CH4 gas retention, and produce gas domes. The latter acts as pockmark precursors whose formation induces a violent gas release to the water column and potentially to the atmosphere. Our study presents a basis for proper upscaling to various effective gassy muddy sediment characteristics and gas retention models. It contributes to the evaluation and even reduction of a long-persisting uncertainty related to the CH4 fluxes from the shallow aquatic sediments.
A unified geodetic data-based earthquake catalog of Taiwan from 2006 to 2018
Authors: Ching Kuo-En , Li Po-I , Chang Wu-Lung , Hsiao Shih-Han , Chen Chien-Liang , Chen Kwo-Hwa
Published: February 2023

A unified geodetic data-based earthquake catalog may provide the asperity information to improve the seismic hazard assessment. Therefore, we propose a unified geodetic data-based earthquake catalog in Taiwan from 2006-2018 using the geodetic data from 333 campaign-mode GNSS stations and 19 precise leveling routes and the published continuous GNSS data to improve the spatial resolution and reliability of vertical component in coseismic displacement fields. The coordinate time series analysis was used to derive the coseismic displacements of each earthquake from the sGNSS and precise leveling data by using the least square method. This earthquake catalog involves 2006 ML 7.0 Pingtung offshore earthquake, 2010 ML 6.4 Jiashian earthquake, March 2013 ML 6.2 Nantou earthquake, June 2013 ML 6.5 Nantou earthquake, 2013 ML 6.4 Ruisui earthquake, 2016 ML 6.6 Meinong earthquake, and 2018 ML 6.2 Hualien earthquake. Then the coseismic source models of these events were evaluated by inverting the coseismic displacement fields. Based on this earthquake catalog, we provided high spatial resolution and precision in the vertical deformation and the resolution of the modeled fault dip angle is also improved. In addition, unknown coseismically reactivated anticlinal structures in SW Taiwan were discovered in this study, which may be associated with the active mud diapirs. Finally, because of abundant coseismic geodetic data adopted in this study, the spatial resolution of coseismic slip distribution is also increased in those earthquake events.
Changes in low clouds optical characteristics in the atmosphere of two different urban sites in Romania
Authors: Saftoiu Golea Genica Liliana , Stefan Sabina , Antonescu Bogdan , Iorga Gabriela
Published: February 2023

The aerosol particles that become condensation nuclei affect the formation and evolution of clouds, their cycle lifetime, and their optical properties, having thus a major impact on the atmosphere, the radiative balance and leading therefore to climate changes. The aim of the study is to investigate the second indirect aerosol effect and the relationship between cloud droplet effective radius and cloud albedo for cleaner and polluted clouds over two sites in Romania (Bucharest and Cluj-Napoca), using satellite data collected from March 2000 to March 2022. Present study is the first one over sites in Romania. A series of physical parameters (albedo, cloud cover fraction, cloud optical depth, liquid water path and cloud water radius) were extracted from the Clouds and the Earth's Radiant Energy System (CERES) database for Bucharest, as a high polluted city, and for Cluj - Napoca, as a cleaner city in Romania. The time series for albedo and low cloud characteristics contained 193.584 hourly profiles. In addition, based on the optical depth from CERES, we calculated low cloud albedo using a parameterization currently used in the climate models. The study was also focused on the life cycle of the low clouds and on the cloud cover fraction over the two sites. The annual and seasonal variations of the cloud physical parameters were investigated and compared for both sites. We highlight how the cloud droplet effective radius modifies differently the cloud albedo for polluted clouds over Bucharest (presence of more and smaller cloud droplets and thus, a higher cloud albedo and less drizzle size drops) than for the cleaner clouds over Cluj-Napoca (presence of fewer and larger cloud droplets, and therefore a lower cloud albedo). The results also shows comparatively the frecqueny of occurence of this type of clouds over both sites and the temporal trend of analyzed physical characteristics. Modifications and variations of cloud characteristics at a city scale help us to better understand the second indirect aerosol effect, life cycle and the climatology of low clouds.AcknowledgmentGLSG, SS and GI acknowledge the support from NO Grants 2014-2021, under contract no 31/01.09.2020, Project EEA-RO-NO-2019-0423. GLSG work was also supported by the University of Bucharest, PhD research grant and by the Romanian Nucleu Programme. 
Optimal Irrigation Water Allocation among Different Growth Stages
Authors: Cai Yu-Syuan , You Gene Jiing-Yun
Published: February 2023

With the increasing impact of global climate change, the effective utilization of water resources become more and more important. Among different water use sectors, agricultural irrigation accounts for about 70% of global water use. Different from other water uses which can be utilized at any time, irrigation is not only a matter of quantity, it is more important to accurately schedule according to the water demand of crops. However, in many studies in the field of water resources or agriculture, the non-rejuvenation of crop growth is usually ignored when calculating crop yield. These studies usually simply assume that irrigation water is effective in each period, and finally add up the yield of each period as the total benefit of irrigation. To solve this problem, the study aims to explore the dynamic decision-making of irrigation schedules with the consideration of uncertainty under water scarcity. Considering the characteristics of crop growth, we propose an analytical model in the form of a max-inf problem to investigate a two-stage stochastic optimal allocation of water to maximize the yield expectations of the two stages. We first assume that the rainfall in the first stage is known, and the rainfall is described by a given probability distribution. With FAO 33, an empirical production function assessing the yield response to water, we need to apply the concept of max-inf to determine the expected yield. Accordingly, we found the optimal condition which maximizes the yield, satisfying a linear relationship between the probability of the first stage dominance and the water demand and yield response factor of the two stages. With this optimal condition, we can use the known crop water demand and yield response factor to estimate the probability of the first stage dominance and adjust the irrigation water to achieve the condition of maximum yield expectation, to achieve the goal of maximum yield. Following, this study proposes four scenarios to examine the optimal decision with numerical experiments, not only to verify the analytic solution but also to examine the decision-making under different conditions. So far the decision is still discussed within the two-stage framework, assuming that the rainfall in the first and second stages is known, and adding the rainfall uncertainty in the third stage to analyze irrigation water. It will extend to the multi-stage framework which could more reasonable presentation of crop yield decisions. In this way, this study can better help us to understand irrigation decision-making among different water supply stages under uncertainty.
Study on the rotation of blocks in two-dimensional block-rock mass
Authors: Jiang Kuan , Qi Cheng-zhi
Published: February 2023

Rock mass has complex block-hierarchical structure involving various scale levels, which should be considered both in dynamic and static conditions. Because the interlayer has weak mechanical properties compared with rock blocks, the deformation of rock mass mainly concentrates at the interlayers both in dynamic and static conditions, which provides the possibility of translation and rotation for rock blocks. The basic carriers of pendulum-type wave in rock mass are geoblocks with translational and rotational degrees of freedom involving various hierarchical levels. The major part of the energy of a blast is spent to fragmentation of rocks and is transferred to rock blocks of the stressed geomedium in the form of kinetic energy (including translational kinetic energy and rotational kinetic energy). The in-situ experimental data has shown that the block-rock mass has significant angular deformation under dynamic impact, and the rotation of blocks can deeply affect the wave propagation and dynamic behavior of rock mass. Previous research on 1D dynamic model of block-rock mass cannot reflect the rotation effect of blocks, and the new 2D dynamic model should take into account the rotation of blocks and energy transfer. Consequently, aiming at the investigation of rotation of blocks, the 2D dynamic model of block-rock mass is established based on the accurate consideration of rotation effect. The research based on this model reveals the mechanism of the rotation of blocks, and determines the characteristics of energy transfer and the influence of the rotation of blocks on the inhomogeneous deformation of interlayers. Research shows that the rotation of blocks is not directly related to whether the structure of rock mass is symmetrical, or whether the interlayer is deformed or not, or the form of external loads, but is caused by the non-equilibrium shear between interfaces in the absence of the external torque. The rotation of blocks results in the inhomogeneous deformation of interlayers, and has a significant influence on the shear deformation of interlayers. At some local positions, in addition to the deformation of the interlayer caused by translation, the block-rock mass also produces additional tension and compression deformation caused by the rotation of blocks, which may lead to the phenomenon of rock crushing. This study theoretically solves the problems of wave propagation in block medium under arbitrary loads and torque, and is helpful for the research of seismic wave propagation in block medium with inhomogeneous complex structures.
Method to evaluate sediment-driftwood transport processes with flood runoff in a basin during heavy rainfalls
Authors: Harada Daisuke , Egashira Shinji
Published: February 2023

Recently, several extreme flood hazards with active sediment and driftwood transport have occurred in mountainous areas of Japan, as typically observed in the Akatani river flood disaster in 2017. Therefore, in order to mitigate such hazards, it is required to develop methods to evaluate flood, sediment, and driftwood runoff from a basin during heavy rainfall. This research proposes integrated methods to evaluate flood, sediment and driftwood runoff from a basin during heavy rainfall using numerical methods. The proposed methods are applied to the Terauchi Dam basin, where large amounts of sediment and driftwood were discharged during the 2017 Northern Kyushu heavy rainfall event, to discuss the applicability of the methods.The methods are composed of a distributed rainfall-runoff model, slope stability analysis, sediment and driftwood transport in the slope based on mass system equation, and sediment and driftwood transport in the river channel by unit channel model. These models are integrated as Rainfall-Sediment Runoff (RSR) model to evaluate sediment and driftwood runoff from a basin. As a result of its application to the Terauchi Dam basin, we found that whether or not the debris flow enters the river channel, i.e., the definition of the upstream end of the river channel, has a significant impact on the results. Therefore, we investigated whether the sediment supplied by debris flow enter the river channel during the actual event. The results show that the upstream end of the river channel in the computation should be defined as approximately 4% to 10% slope, and in case the mesh size is sufficiently fine, the debris flow inflow into the channel is sufficiently evaluated. In conclusion, this research proposes an integrate methods to evaluate flood, sediment and driftwood runoff from a basin, and discusses its applicability to the disasters such as the 2017 Northern Kyushu heavy rainfall event.
Is Argentina hotter? Understanding heatwaves temporal and spatial behavior using the ERA5-LAND dataset (1950-2022)
Authors: Cimolai Caterina , Aguilar Enric , Zaragozí Benito , Olano Pozo Jon , Boqué Ciurana Anna
Published: February 2023

Climate strongly impacts socio-ecologic systems. Increasing the intensity and frequency of heatwaves is one of its major consequences. Heatwaves are periods of consecutive days when temperatures are much hotter than normal. Cities are especially affected because their impact is usually aggravated by the Urban Heat Island (UHI), an intrinsic phenomenon that increases urban temperatures compared to surrounding rural areas. Extreme hot temperatures affect urban areas causing health problems, increasing energy requirements, and altering water supplies, among others.  Heatwaves have been studied in Argentina but this has not been updated for the whole country recently. Due to these impacts on people’s well-being, infrastructure, and ecosystem functioning, this work proposes to study changes in spatial distribution and frequency of heatwaves in Argentina.  We use the ERA5 LAND dataset and the HeatWaver R package to identify heatwaves over mainland Argentina. For the purpose of this study, we define heatwaves as periods where maximum and/or minimum temperatures are above the 90th percentile of the WMO standard reference period (1961-1990) during five or more consecutive days. We inspect the temporal and spatial extent of the phenome and monitor its changes over time. In agreement with global warming tendencies, heatwaves are more frequent, and a larger portion of the country has been under stress in recent years. We also inspect the heterogeneous impact over the territory and large cities.  To understand the impact of heatwaves in cities, it is crucial to evaluate the risk, which is the conjunction of hazards, exposure and vulnerability. As a first step, this work studies heatwaves as hazards while those other aspects will be incorporated into future research. Our final objective is to reach an urban heatwave risk index, combining meteorological, environmental, urban, and social aspects. This indicator would liaise climate science with local and regional policies and offer information for adaptation and mitigation policies to face climate variability and change.  Keywords: heatwaves, cities, climate change, Argentina. 
Quality assessment of the gridded climate indices estimated from GNSS displacements for the European area
Authors: Lenczuk Artur , Klos Anna , Bogusz Janusz
Published: February 2023

For more than 30 years, the Global Navigation Satellite System (GNSS) has successfully detected local crust deformations. These changes in deformation are caused, among other things, by changes in Total Water Storage (TWS), which reflect regular changes in the water system, but are also coupled with changes resulting from unexpected climate change. Current water conflicts caused by climate variability, increased human activity, population growth and food demand are leading to an increased importance of monitoring the abundance of the terrestrial hydrosphere. Such monitoring is increasingly being carried out using GNSS observations, mainly due to the impressive number of permanent stations distributed on Earth. However, the distribution of GNSS stations is irregular, and the displacement time series is often incomplete. Moreover, because of systematic errors, consistency of several parameters estimated for nearby GNSS stations may be very low. To eliminate the impact of these errors, but still capture regular changes in the climate system, we estimated drought severity index (DSI) using GNSS displacement time series over Europe, and interpolated these station-based DSI values over European area in a 1 per 1 degree grid. The quality of interpolated GNSS-DSI values has been assessed using four external datasets: (1) the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) data, (2) combination of GRACE/-FO data with the Satellite Laser Ranging (SLR) data, provided by the University of Bonn, (3) combination of SLR data and high-low Satellite-To-Satellite Tracking (hlSST) data, provided by Leibniz University Hannover, and (4) the self-calibrating Palmer Drought Severity Index (scPDSI). The external datasets have low spatial resolution, when compared to station-dependent GNSS-DSI and the scPDSI index is unable to capture several real water changes. Using GNSS displacements for estimated of DSI reduces these limitations. Our results show that GNSS-based DSI is spatially coherent with indicators derived from other datasets and is able to map dry and wet periods occurring over Europe. GNSS-DSI are also able to capture extreme short events not observed by other datasets. We note that the GRACE-DSI values show the least consistency with GNSS-DSI values. We find also that the DSI values estimated from combined GRACE and SLR indices have largest root-mean-square values for Europe. Our results show that GNSS displacements can be applied to study human and/or climate impact on water changes in small spatial and temporal scales, which may be averaged out in the other datasets; this hold the true especially in regions where GNSS stations are densely distributed.
Oceanic crustal structure at ODP Site 1256 from seismic wide-angle tomography and down-hole logging
Authors: Grevemeyer Ingo , Henstock Timothy J. , Dannowski Anke , Marjanovic Milena , Hilbert Helene-Sophie , Li Yuhan , Teagle Daman A. H.
Published: February 2023

Our view on the structure of oceanic crust is largely based the interpretation of seismic refraction and wide-angle experiments, revealing that the upper basaltic crust (layer 2) is a region of strong velocity gradients. In contrast, the lower gabbroic crust (layer 3) is relatively homogeneous, although it generally displays a gentle increase in velocity with depth. Furthermore, the upper crust has been sub-divided into layer 2A, composed of extruded basalts, and layer 2B, formed by basaltic sheeted dikes. Site 1256, drilled during the Ocean Drilling Program (ODP) into the upper crust and later extended into the uppermost gabbroic crust during the Integrated Ocean Drilling Program (IODP), is among the deepest drill sites sampling intact oceanic crust. It is the only site world-wide that crossed the entire basaltic upper crust, reaching plutonic rocks at ~1.35 km below the top of the basement, recovering 150 m of dominantly gabbroic rocks at the base of the hole. Three campaigns of down-hole logging at hole 1256D provided a unique set of high-resolution sonic-log velocities of seismic layer 2 and from the uppermost top of seismic layer 3. However, Hole 1256D was drilled at a site with rather limited seismic data coverage, especially lacking seismic refraction and wide-angle profiling. During a seismic survey of the RRS JAMES COOK in the Guatemala Basin in December of 2022, a seismic profile with 12 Ocean-Bottom-Seismometers spaced at 7 km intervals, receiving signals from a tuned airgun array of 4500 cubic-inches shot at 150 m spacing was collected. The data provide excellent seismic records to derive a detailed sound-velocity model of the oceanic crust at the drill site from tomographic travel time inversion of first arrivals (Pg, Pn) and a prominent wide-angle reflection from the crust-mantle boundary (PmP) or seismic Moho. The results show that the seismic structure along the 115 km long line is extremely homogeneous. The velocity-depth profile from tomography further provides an excellent low-frequency match of the down-hole logging observations, supporting that modern seismic data are a powerful remote sensing tool to study the oceanic crust and lithosphere. An interesting observation is that the thickness of the oceanic crust at Site 1256 is extremely thin at only 4.6 to 5.1 km, compared to a global average thickness of about 6 km. This appears to be a regional feature supported by another seismic profile about 150 km north-eastwards. The thin crust agrees with a weak seismic event at ~6.8 s two-way travel time (twtt), i.e., ~1.6 s twtt below basement obtained from re-processing 6-km-long streamer data from the ODP pre-site survey at Site 1256. 
Impacts of Farmland Irrigation on Land Surface Water and Energy Balance over a Humid Region: Development and Benefits of a Crop-Classified Dynamic Irrigation Scheme in Noah-HMS
Authors: Yang Qianya , Wei Jianhui , Yang Chuanguo , Yu Zhongbo
Published: February 2023

Irrigation practice has impacts on the natural environment by changing the water and energy balance at the land surface and thereby interacting with the atmosphere. To quantify such impacts and estimate irrigation water demand, process-based hydrological models with a representation of irrigation practice are often used. However, the applicability of existing irrigation schemes is limited to arid and semi-arid regions. Likewise, it is still lack of more sophisticated irrigation schemes that can be particularly applicable to humid regions. This study presents the newly developed Crop-classified Dynamic Irrigation (CDI) scheme that has been two-way coupled into the land surface-hydrologic model Noah-HMS. Such development allows to distinguish the different irrigation practices for "rice" and "non-rice" crops and to estimate irrigation water demand. We have applied the newly developed model to an important grain and industrial crop production base in southern China, namely, Poyang Lake Basin (PLB), where the sown area of rice accounts for more than 60% of the sown area of all crops. As compared to the widely used, traditional Dynamic Irrigation (DI) scheme, the CDI-incorporated Noah-HMS improves the simulations of water and energy balance over the PLB from 2007 to 2015, especially irrigation water amount simulation. The relative error for irrigation water amount of CDI (DI) is -18.1% (-56.8%). In terms of surface water balance, the inclusion of irrigation practice has larger impacts on the simulated soil moisture (+1.7%) during dry years than that (+0.9%) during wet years, while has larger impacts on the simulated surface runoff (4.6%) in wet years than that (2.4%) in dry years. In terms of surface energy balance, irrigation practice leads to increased latent heat flux by 0.9 W/m2 (1.4%), decreased sensible heat flux by 0.5 W/m2 (1.3%), decreased ground heat flux by 0.02W/m2 (5.0%), and increased net radiation by 0.09 W/m2 (0.1%). Such impacts on the surface water and energy balance become more pronouncing at local scale especially over the intensively irrigated areas, for example the Nanchang city region. We conclude that our Crop-classified Dynamic Irrigation scheme is especially beneficial for applications in multiple cropping humid regions. Furthermore, our modeling development has the potential to be further extended into the fully coupled atmospheric-hydrologic modeling systems with a more holistic representation of human activities.
Emission trend and drivers of CO2 emission in Chinese cities from 2012 to 2018
Authors: Shi Qinren , Zheng Bo , Zhang Qiang , He Kebin
Published: February 2023

China has pledged to peak CO2 emissions before 2030 and achieve carbon neutrality before 2060, and climate actions are urgently needed. Cites are basic administrative units and leaders in implementing emission reduction policies in China, and a comprehensive analysis of characteristics and historical emission trends in Chinese cities is of great importance. This study developed a city-level CO2 emission inventory in China during 2012-2018 by merging multiple databases. The results reveal spatial heterogeneity and inequality in Chinese cities’ CO2 emissions. In general, eastern cities emit more CO2 than western cities. According to the emission-Lorenz curve, the top 10% of 336 cities contribute over 30% of total CO2 emissions in 2018. From the perspective of emission trends, more than 60% of cities in China failed to achieve the decoupling of GDP growth and carbon emissions. The overall positive correlation between per capita GDP and per capita carbon emission in Chinese cities indicates that even cities with a relatively high level of development still need to further promote carbon emission reduction. As for sectoral drivers, industrial boilers and cement sectors were the major drivers for CO2 emission reduction in most cities, while the increase in carbon emissions from thermal power and industrial boiler sectors led to the rebound of carbon emissions in most cities.