bluuebunny/crossref_metadata_2025 huggingface dataset:
 Daily Streamflow Simulations Improvement in Data Scarce Watersheds using different Optimization Techniques and Calibration Methods
Authors: Ait naceur Khaoula , El khalki El mahdi , Hadri Abdessamad , Jaffar Oumar , Brocca Luca , Saidi Mohamed El mehdi , Tramblay Yves , Chehbouni Abdelghani
Published: March 2024

Hydrological modeling is critical for effective water resources management, especially in developing countries such as Morocco where data are scarce. This study aims to improve daily river discharge predictions in 26 Moroccan catchments from 1993 to 2019. It evaluates the GR4J and MISDc models, focusing on optimizing their performances using four optimization techniques: Particle Swarm Optimization (PSO), the Nelder-Mead simplex algorithm (FMIN), Simulated Annealing (SA), and the Genetic Algorithm (GA). The two hydrological models are coupled with six calibration methods to provide the different ranges of uncertainties and to assess their consistency across diverse datasets. The methods include the split-sample or half-half method, the odd/even year method, as well as the calibration on a longer period than validation and vice versa. In addition, the Kling-Gupta Efficiency (KGE) and the relative bias were used as performance criterions. Due to the high elevation of some catchments studied and to the important amount of the snowmelt contribution in the river discharge at their outlets, a snow module incorporation was necessary to assess whether snowmelt impacts runoff or not. The outcomes demonstrate that all algorithms were able to successfully calibrate the GR4J and MISDc models (-0.26
Clock skew corrections of a large-aperture OBS array in the Atlantic Ocean reveal the need to include non-linear drift corrections
Authors: Krueger Frank , Cabieces Roberto , Harris Katrina , Ferreira Ana , Tshekmistrenko Maria , Hicks Stephen , Geissler Wolfram , Hannemann Katrin , Schmidt-Aursch Mechita
Published: March 2024

Accurate timing corrections for seismic data recorded by ocean bottom seismometers (OBS) are essential for a wide range of applications. The synchronization of internal OBS clocks with Global Positioning System (GPS) is only possible prior and subsequently to deployment in the seafloor. Thus, untracked, possibly nonlinear clock errors in seismic data may accumulate over the deployment period. The measurement of the clocks offset from GPS at retrieval, referred to as `skew’, can be used to correct the data solely under the assumption of a uniform rate of clock drift throughout the whole deployment. We estimate OBS clock drift curves for 40 OBSs of the large-scale UPFLOW amphibian array in the Madeira-Azores-Canaries region that lasted ~14 months in 2021-22. We use the relative shift of daily Empirical Green Functions obtained from seismic ambient noise recorded by all available data channels to track clock error. We find that 95% of our OBS clock drift observations have a substantial non-linear component, notably in the first months of the deployment. Overall, our estimated time-dependent clock drift curves accurately predict the final skew, with an average difference of ~160 ms to GPS skew values obtained at retrieval. We test our skew curves by using them to correct examples of recordings of teleseismic earthquakes and of local-regional seismicity. Uncertainty analysis of the skew curves gives a mean skew error of ~110 ms, indicating the suitability of the corrected data for future seismological studies such as for seismic tomography, seismicity analysis and moment tensor inversions. A dedicated open-source Graphical User Interface toolbox in Python 3 has been developed to facilitate OBS clock synchronization using seismic ambient noise.
Big Slip on Small Faults - How Does Extreme Fault Slip Occur on Short-to-Moderate Length Faults
Authors: Furlong Kevin P. , Herman Matthew W. , McKenzie Kirsty A.
Published: March 2024

A general correlation between maximum co-seismic fault slip and fault length has been well constrained by observations from numerous earthquakes occurring on many crustal faults. In spite of this global consistency, there are notable examples of co-seismic fault slip magnitudes that far exceed the expected maxima for the fault dimensions.  Two instances of extreme fault slip that occurred on short-to-moderate length upper-plate faults in subduction systems, where the megathrust lies at shallow depths are the 2016 Kaikoura (New Zealand) earthquake, and the 1855 Wairarapa (New Zealand) earthquake. In both cases, co-seismic fault slip was 5 to 10 times greater than expected from the rupture length - fault slip scaling relationships. The typical crustal fault model  is a fault with a brittle-to-ductile transition at depth; in this scenario, co-seismic slip is inhibited by viscous resistance from the deeper, ductile component of the fault.  In contrast, the tectonic characteristics of faults that experience extreme co-seismic slip, involve upper plate faults that truncate against the megathrust at seismogenic depths (i.e. are fully frictionally coupled over their entire depth extent). During a megathrust earthquake, the plate interface unlocks and upper-plate faults that extend to the ruptured plate interface transiently experience free-slip boundary conditions on both their upper (surface) and lower (megathrust) ends. As a result, such upper-plate faults can potentially experience full strain release (and therefore maximum slip), independent of their length. For appropriately oriented faults, this effect may be enhanced by co-seismic stress changes associated with the megathrust earthquake. Geologic evidence of large displacement (and/or displacement rate) upper-plate faults in other subduction systems indicates this process may commonly occur. One example is a set of upper-plate faults along the Cascadia margin (near Newport, Oregon), that have strike-slip geologic slip rates, averaged over 10s of thousands of years, exceeding tens of mm/yr and approaching local plate convergence rates. These upper-plate Cascadia faults are also located where the plate interface is sufficiently shallow and seismogenic, indicating that these high-slip, upper-plate faults are likely frictionally locked over their entire depth range. In spite of the high overall slip rates of these upper-plate faults, because they are locked along their entire depth extent between earthquakes,  they may be unrecognized by inter-seismic geodetic observations.
Teaching Climate Change: using Earth Learning Ideas
Authors: Loader Pete , Realdon Giulia , Coupechoux Guillaume , Juan Xavier , P. Correia Gina
Published: March 2024

Global anthropogenic climate change is real and so it is essential to include this topic in our curricula to enable students to understand the scientific evidence and the possible effects this might have on our lives.This poster provides an insight into some of the practical ways that climate change topics might be taught using the free online ‘Earthlearningidea’ website (https://www.earthlearningidea.com/English/Resources_and_Environment.html#clchange). As such, it is designed to reflect the GIFT 2024 workshop run by our EGU Geoscience Education Field Officers and to demonstrate the range of ELIs undertaken in their respective countries. It is also presented in fond memory of Professor Chris King who was the instigator and inspiration of this and so many other geoscience education projects in the UK and abroad.                                   These climate change activities and others are available at the Earth learning website (https://www.earthlearningidea.com/), a repository containing more than 400 activities ready to use and translated into different languages. All are designed to develop students’ critical thinking and research skills, while developing their knowledge and understanding of Earth processes and products.EGU Geoscience Education Field Officers (GEFO) are a team of geoscience teachers and researchers who provide professional development to schoolteachers who have elements of geoscience in their teaching curricula, through interactive hands-on workshops. The team is supported by the European Geosciences Union Education Committee and is active in eleven countries around Europe. (https://www.egu.eu/education/).
HIPER motivated students follow the SUPER-MOUV sea campaign
Authors: Berenguer Jean Luc , Gendron Faustine , Saliby Christelle , Balestra Julien
Published: March 2024

The coasts of Ecuador and Colombia have been hit by several earthquakes of magnitude greater than 7.5 over the course of the 20th century. An earthquake of magnitude 7.8 struck near the town of Pedernales in April 2016. It was the most powerful earthquake to hit Ecuador in 70 years, claiming hundreds of lives and causing hundreds of millions of dollars in economic losses. The seismic data revealed the complex slip behaviour of this part of Ecuador's subduction zone. The shallow part of the megafault is characterised by slow-slip earthquakes that can last from a few days to a few months and do not generate seismic waves (asismic rupture), so are not felt by the population. What controls these slip events is still poorly understood, even though they play an important role in the seismic cycle that governs the periodic loading and release of the megafault. The aim of recent oceanographic missions (the HIPER and SUPER-MOUV expeditions) is to understand how structure, temperature and fluids affect slip behaviour and the transition from seismic to asismic rupture. Many schoolchildren were involved in these scientific missions, following the mission's progress on a daily basis. Each following school was in contact with an education team on board and on land. Working closely with the researchers, the pupils were able to follow the work on board the ships, solve weekly scientific puzzles and take part in live video conferences from the oceanographic ship. Allowing students, the future citizens of the world, to experience first-hand how science works... these are essential elements in strengthening the link between science and society. 
Simulating glacial-interglacial CO2 variations: What's right with CLIMBER?
Authors: Heinemann Malte , Brovkin Victor , Willeit Matteo , Segschneider Joachim , Schneider Birgit
Published: March 2024

Despite intense efforts, current generation comprehensive Earth system models have, to our knowledge, not been able to simulate the full extent of the atmospheric pCO2 drawdown (as recorded in ice cores) during the Last Glacial Maximum (LGM). Yet, the intermediate complexity model CLIMBER-2 has successfully been used to simulate not only the LGM drawdown but also the transient evolution of CO2 concentrations during entire glacial–interglacial cycles. To better understand why this is the case, we compare the CLIMBER-2 results to pre-industrial and LGM simulations using two related models with increasing complexity, namely, the recently developed intermediate complexity model CLIMBER-X and the state-of-the-art comprehensive Earth system model MPI-ESM as used in the PalMod project, focusing on ocean carbon cycle changes.
3D numerical simulation of complex in-situ stress fields in shale reservoirs: A case study in the northwestern Junggar Basin of China
Authors: Chen Peng , Qiu Huaning , Chen Xinyu
Published: March 2024

AbstractThe shale reservoir in the Lower Permian Fengcheng Formation of Mahu Sag, the Junggar Basin is prospective in hydrocarbon exploration and development. Due to the complex structures of the study area and the strong heterogeneity of shale reservoirs, the distribution of in-situ stress in the research area has always been poorly understood. Previous studies on in-situ stress are mostly limited to mechanical experiments, logging calculation and simple 2D numerical simulations. Nevertheless, this study combines multiple technical means to simulate the complex 3D in-situ stress in a more accurate and precise way. In this study, a detailed geological model was established by utilizing the method of ant tracking. Post-stack acoustic impedance, logging data and acoustic emission tests were used to jointly invert the accurate 3D geomechanical model. The orientation of the in-situ stress in the study area was determined by digesting the information from FMI (Formation MicroScanner Image) while the boundary condition was fixed by acoustic emission experiments. Finally, the in-situ stress distribution of the study area was clarified through finite element numerical simulation. As is shown by the simulation results, the in-situ stress modeling revealed that the complicated stress state, stress differences, and stress difference coefficients, all of which can provide valuable guidance for well deployment optimization and hydraulic fracturing in the study area, are closely related to burial depth, faults, and rock mechanics parameters. The stress regime in the research area is mainly reverse faulting type. However, as the burial depth increases, the stress regime will change accordingly, transforming from reverse faulting stress regime to strike-slip faulting stress regime. In the same time, the existence of faults will also affect the stress regime to a certain degree. In addition, most faults in the research area are stable and show little tendency of slippage, but there may be a higher risk of slippage in the deep strata. Therefore, it is advisable to avoid these areas as much as possible during geological exploration.Keywords: 3D in-situ stress field, numerical simulation, shale reservoir, Mahu Sag
Huge Ensembles of Weather Extremes using the Fourier Forecasting Neural Network
Authors: Collins William , Pritchard Michael , Brenowitz Noah , Cohen Yair , Harrington Peter , Kashinath Karthik , Mahesh Ankur , Subramanian Shashank
Published: March 2024

Studying low-likelihood high-impact extreme weather and climate events in a warming world requires massiveensembles to capture long tails of multi-variate distributions. In combination, it is simply impossible to generatemassive ensembles, of say 10,000 members, using traditional numerical simulations of climate models at highresolution. We describe how to bring the power of machine learning (ML) to replace traditional numericalsimulations for short week-long hindcasts of massive ensembles, where ML has proven to be successful in terms ofaccuracy and fidelity, at five orders-of-magnitude lower computational cost than numerical methods. Becausethe ensembles are reproducible to machine precision, ML also provides a data compression mechanism toavoid storing the data produced from massive ensembles. The machine learning algorithm FourCastNet (FCN) isbased on Fourier Neural Operators and Transformers, proven to be eﬃcient and powerful in modeling a widerange of chaotic dynamical systems, including turbulent ﬂows and atmospheric dynamics. FCN has already beenproven to be highly scalable on GPU-based HPC systems. We discuss our progress using statistics metrics for extremes adopted from operational NWP centers to showthat FCN is sufficiently accurate as an emulator of these phenomena. We also show how to construct hugeensembles through a combination of perturbed-parameter techniques and a variant of bred vectors to generate alarge suite of initial conditions that maximize growth rates of ensemble spread. We demonstrate that theseensembles exhibit a ratio of ensemble spread relative to RMSE that is nearly identical to one, a key metric ofsuccessful near-term NWP systems. We conclude by applying FCN to severe heat waves in the recent climaterecord.
Modeling the impact of climate and land use changes on future water resources dynamics in central Sicily, Italy
Authors: Tekle Shewandagn Lemma , Bonaccorso Brunella
Published: March 2024

Drought events, worsened by climate change, produce detrimental impacts on freshwater availability especially in arid and semi-arid regions. The situation becomes more critical when these hydrologic extremes combine with land use change mainly caused by anthropogenic factors, such as urbanization, intensive farming, and industrial activities. The present study is designed to investigate the combined impacts of climate and land use changes on the future freshwater  stored in the artificial reservoirs of three adjacent river basins located in the central Sicily (Italy), i.e: Verdura (2 active reservoirs with capacities 9.2 Mmc and 4.19 Mmc), Imera Meridionale (one active reservoir with capacity 15 Mmc), and Platani (one active reservoir with capacity 20.7Mmc), using the Soil and Water Assessment Tool (SWAT) model. The reservoirs are used for irrigation, drinking water supply, and electric power generation. Future climate variables such as rainfall, minimum and maximum temperatures were derived from an ensemble Regional Climate Models for two main representative concentration pathway (RCP) scenarios, such as an intermediate emission scenario (RCP4.5) and a severe emission scenario (RCP8.5). A coupled multi-layer perceptron neural networks and cellular automata (MLP-CA) model was implemented to simulate future land use of the region considering the CORINE land cover in 2000, 2006, 2012, and 2018 as a reference dataset. The future land use is then projected until the mid-century (2048) in a six-year interval using the validated MLP-CA model. The soil data from the European soil data center (EUSDAC) was used as input for the SWAT model. The result indicated that the basins could experience a decrease in inflows to the reservoirs. The separate evaluation of climate change and land use changes indicated that the effect of climate change on streamflow variation is more pronounced than the effect of land use change only. In this study, we introduced new hydrological insights into the region by analyzing the attributions of climate change, land use change, and coupled climate and land use changes on the future freshwater availability which were overlooked in the previous studies. The implementation of the proposed approach can contribute to design environmentally sustainable and climate resilient river basin management strategies. Keywords: MLP-CA, Land use change, Climate change, SWAT, Hydrological modeling, Water availability
LEO constellation-augmented SBAS and performance simulation analysis
Authors: Wang Le , Yang Weicong , Huang Guanwen , Wang Ziwei
Published: March 2024

Satellite-Based Augmentation System (SBAS) relying on ground monitoring networks can only provide regional services in their own countries or regions. DFMC can expand service coverage and improve service quality, but it still needs the support of the ground monitoring network. Equipped with a spaceborne receiver, LEO has a unique advantage in space-based monitoring, which is expected to expand the service coverage and improve the service performance of SBAS. A global integrity monitoring method of SBAS combining LEO satellites and regional ground station data is proposed. Based on simulation data, the improvement effect of this method compared with that of relying solely on ground station data is verified from the aspects of correction sequence, monitoring arc integrity, enhanced satellite number and coverage. The results of global user positioning accuracy, integrity and usability evaluation are also given. The results show that this method can effectively extend the service coverage of SBAS and improve its performance. On a global scale, the average horizontal positioning accuracy of users is better than 0.5m and the average vertical positioning accuracy is better than 1 m. The pseudo-range residual reduction reached 21%, and the availability met the requirements of APV-I. The addition of LEO can effectively expand the monitoring and service scope of BDSBAS and improve its performance.
Water column can shift from sinks to sources of CH4 with increasing river size
Authors: Wang Junfeng , Xia Xinghui
Published: March 2024

CH4 production in freshwaters has been considered to occur primarily in anoxic sediments. However, recent discovery of oxic CH4 production in some lake waters makes the origins and controls over the fate of cumulative CH4 in water column elusive. Especially, whether CH4 can be produced in oxic water column of river systems remains unclear, and the role of water column in CH4 emissions is poorly understood across different river sizes. Here, we present water column contributions to riverine CH4 emissions based on 4-year national-wide in situ measurements across six large river networks with stream order from 3rd to 8th. We find water column acts as a contributor of CH4 net production in 58% observations, indicating the occurrence of CH4 production in oxic water column, which is probably attributed to CH4 production in anoxic interface of suspended particles and production by phytoplankton. Water column can account for 7% of riverine CH4 emissions on average across all observations. Water-air CH4 fluxes decreased exponentially with stream order. In contrast, water column contribution increased with stream order and its roles vary with river size and shift from CH4 sinks in streams to CH4 sources in large rivers. Water column can consume 6% of CH4 released from sediment in rivers of size lower than 6th, while contribute 12% to water-air CH4 fluxes in higher-order rivers. This shift is mainly attributed to the increase of river depth and higher concentrations of suspended particles, which may facilitate net CH4 production in water column of large rivers. Our findings suggest oxic CH4 production in water column represents a hitherto overlooked source of methane and can be important for CH4 cycling and emissions in river systems, especially for large rivers.
Investigation on combustion characteristics and molecular structures of Heiyanquan coal in Santanghu coalfield ,Xinjiang, China
Authors: Feng Tong , Zeng Qiang
Published: March 2024

Fossil energy such as coal is the main source of energy in the world, in order to better understand the combustion process of coal, the present study takes the coal of Santanghu in Xinjiang as the research object, and the structural parameters of the coal are obtained by using experiments such as ultimate analysis, X-ray photoelectron spectroscopy(XPS), Nuclear magnetic resonance carbon spectrum (13C-NMR), etc. Based on which, the structure of the molecular model of the coal at room temperature is constructed, geometry optimization and annealing optimization of the constructed coal molecular model was carried out using Materials studio software. And the coal samples were heated to different temperature points and analyzed the variation rules of activation energy, functional groups and stripe orientation and length features at different stages of the combustion process using Fourier transform infrared spectrometer (FTIR), Thermogravimetry (TG) and High resolution transmission electron microscope (HRTEM) experiments .The results showed that the molecular formula of the Santanghu coal was C175H125O21N3.As the temperature increases, the reaction process of the water loss and drying phase of spontaneous coal combustion becomes longer, while the oxidation and weight-gaining phase becomes significantly shorter, and the change of the combustion phase is relatively stable.This study is instructive for the efficient utilization of coal, and is important for improving the utilization efficiency of coal energy and protecting the ecological environment, and provides a certain theoretical basis for the spontaneous combustion and mining of actual coal samples.
Investigating the synergistic cooling effect of urban blue and green spaces via an advanced urban canopy model
Authors: Shi Dachuan , Song Jiyun
Published: March 2024

Urban overheating is becoming an increasingly pressing concern under the dual challenges of global warming and urban heat island effect. One effective way to mitigate urban overheating problems is to create urban cool spots via urban blue-green spaces (BGS).  To investigate the synergistic cooling effect of urban BGS, we proposed a new urban BGS coupling system by integrating a new urban water module with the state-of-the-art urban vegetation module in the framework of an urban canopy model (UCM). This coupled BGS system can represent complicated radiative exchanges between building, tree, and water, and simulate dynamic variations of shadow length, temperature, humidity, as well as energy and water fluxes within the urban street canyon. The new urban BGS model has been evaluated in typical neighborhoods with building and trees siting along rivers (also named ‘water towns’) in two Chinese megacities, i.e., Shanghai and Hong Kong. Based on this model, we investigated the synergistic cooling effect of BGS in different ‘water town’ design scenarios with different combinations of BGS characteristics (e.g., tree crown radius and height, river width, the distance between tree and river) and street canyon characteristics (e.g., geometries and orientations). Our study emphasizes the importance of optimizing 'water town' design to offer more effective cool spots for urban citizens facing escalating heat stress.
WebGPlates: A Unity-based Tool For Enhancing Paleogeographic Research
Authors: Li Haipeng , Cheng Han , Zahirovic Sabin , Wang Yisa
Published: March 2024

GPlates, an open-source, cross-platform GIS software, has been pivotal in plate tectonics and paleogeography. The recent browser-based implementation of GPlates, facilitated by pyGPlates and Cesium, offers real-time rotation of online datasets. Yet, this approach encounters limitations in data rotation efficiency and integration with diverse datasets. To address this issue, we introduce the Unity-based WebGPlates (https://dplanet.deep-time.org/DPlanet/), which harnesses the capabilities of the Web Assembly and Unity framework for enhanced computing efficiency and browser-based rendering. More importantly, WebGPlates integrates with the Deep-time Digital Earth Platform, ensuring comprehensive data access and services. Our preliminary results highlight the potential of WebGPlates as an indispensable tool in paleogeographic research. We extend an invitation to the whole community to engage and collaborate utilizing this enhanced platform.
Water transport in agricultural soils estimated by time-lapse electrical resistivity tomography technique
Authors: Liu Jia-Wei , Chang Young-fo , Liu Tsang-Sen
Published: March 2024

It is well-recognized that soil moisture plays an important role in the management of water resources, as well as soil and crop production. This research proposed the use of time-lapse Electrical Resistivity Tomography (ERT) to overcome the limitations of point-based soil moisture measurement, which often fails to capture detailed spatiotemporal data. ERT is a widely used geophysical technique for the non-destructive exploration of subsurface media’s resistivity. Since the electrical resistivity is sensitive to the water content in soil, the variation of the soil’s resistivity in time and space can be obtained by using this technique that can be correlated to water transport in soil. Thus, using time-lapse ERT for the exploration of water transport in the soil was launched in this study.This research conducted a time-lapse ERT survey executed in a farm during a sprinkling rainfall. A 50 meters time-lapse ERT survey was employed for 29 days with a hybrid-array configuration at a fallow land. The electrode spacing was 1 meter and measurement were conducted every 2 hours, thus a resistivity section of the land with 50 meters in length and 4 meters in depth was estimated with a period of 2 hours. In addition, five moisture meters were set up in the middle of the ERT survey line and at depths of 10, 20, 30, 50, and 100 cm, respectively. Then, the variation of the resistivity was compared with the precipitation data and the soil moisture readings from the meters. The results showed that the decrease of soil resistivity was consistent with the increase of the precipitation and soil moisture. The water transport rates in soils estimated by this technique and moisture meters were similar, they were 20 mm/hour and 16 mm/hour, respectively.This study demonstrates that time-lapse ERT is an effective tool for dynamically monitoring water transport in soils. By employing this technique, near real-time 2D soil moisture monitoring becomes feasible, which could significantly enhance the optimization of water resources and crop production, when integrated with an automatic irrigation system.
Surface current prediction in the seas around the Korean peninsula using a CNN-based deep-learning model 
Authors: Park Jae-Hun , Chae Jeong-Yeob , Kim Young Taeg
Published: March 2024

Prediction of sea surface current is essential for various marine activities, such as tourist industry, commercial transportation, fishing industries, search and rescue operations, and so on. Numerical forecast models make it possible to predict a realistic ocean with the help of data-assimilation and fine spatial resolution. Nevertheless, complicated numerical prediction model requires heavy power and time for computation, which initiated development of novel approaches with efficient computational costs. In that sense, artificial neural networks could be one of the solutions because they need low computational power for prediction thanks to pre-trained networks. Here, we present a prediction framework applicable to the surface current prediction in the seas around the Korean peninsula using three-dimensional (3-D) convolutional neural networks. The network is based on the 3-D U-net structure and modified to predict sea surface currents using oceanic and atmospheric variables. In the forecast procedure, it is optimized to minimize the error of the next day’s sea surface current field and its recursively predicting structure allows more days to be predicted. The network’s performance is evaluated by changing input days and variables to find the optimal surface-current-prediction artificial neural network model, which demonstrates its strong potential for practical uses near future.
Study on the Effect of DTPMP Inhibitor on Oxidation and Structural Characteristics of Coal Spontaneous Combustion
Authors: Zhang Wanling , Zeng Qiang
Published: March 2024

Preventing coal spontaneous combustion fire by using inhibitor is an effective control measure. The oxidized spontaneous combustion characteristics of coal can reflect the performance of coal, and a suitable structural model can reflect the performance of coal more intuitively, and can also lay the foundation for the study of the action mechanism of the inhibitor. In this study, samples from Baishihu coal mine were selected, and diethylenetriaminepenta-methylenephosphonic acid (DTPMP) was used as a blocking agent to investigate the macromolecular structure, microcrystalline structure changes and oxidation process of coal by X-ray photoelectron spectroscopy (XPS), carbon nuclear magnetic resonance (13C-NMR), and Fourier infrared spectroscopy (FTIR). The molecular formula C198H164O40N2 and the molecular structure model were obtained. ChemDraw and Materials Studio were used for the experimental data, and high-resolution transmission electron microscopy (HRTEM) was used to verify the aromatic ring structure built to make the constructed structural model more accurate. In the water evaporation stage, the high ring aromatic layer is converted into the low ring number. Furthermore, in the high-temperature stage, the low ring aromatic layer is transformed due to the coking and condensation reaction of the coal sample. With the increase in the treatment temperature, water loss is heavier, oxygen absorption and weight gain are perplexing, and the value of the burnout temperature is higher. The elemental composition of the coal samples was changed after the addition of the hindering agent, and the temperature at which small free radical molecules were produced and the time at which gaseous products appeared during the coal-oxygen reaction were delayed. The characteristic temperature increases with the increase of the resist concentration and the activation energy decreases in the water evaporation stage and increases in the other two stages. The apparent activation energy of the coal-oxygen reaction increases and the reaction becomes more hard and complex to realize. DTPMP mainly reacts with free radicals and reactive oxides and forms an adsorption layer on the coal surface. And the molecular structure of the inhibitor contains several phosphate functional groups, which can react with the oxides in the coal to form phosphate substances and fill the pores in the coal. It can reduce the evaporation of water and the contact of coal samples with oxygen. These mechanisms interact with each other and together reduce the reactivity of the coal and the risk of spontaneous combustion. This study furthers the understanding of coal spontaneous combustion in this mining area, provides a reference for the prevention and control of coal spontaneous combustion.
Magmatic flare-up recorded in Rb-Sr reset-ages during Gondwana break-up, Kohler Range, Marie Byrd Land, Antarctica 
Authors: Nebel Oliver , Ali Zarin , Raveggi Massimo
Published: March 2024

The Rb-Sr dating system has long been recognised as being susceptible to thermal perturbation. Its so-called closure temperature (TC) in biotite, the lowermost temperature at which interstitial diffusion of radiogenic 87Sr is no longer facilitated, is ca. 400 ˚C, much lower than e.g., the commonly used U-Pb system in zircon in excess of 900 ˚C. Newly developed in-situ analyses or Rb-Sr isotope systematics in biotite using a collision cell mass spectrometer (ICP-MS/MS) have now enabled rapid dating using multiple grains and with high spatial resolution (on a single grain scale). This now allows making use of the thermal characteristics of this dating tool. However, the modes and degrees of isotope reset are still poorly understood. Here, we analyse rocks from the Kohler Range in Antarctica for their Rb-Sr systematics in biotite. The plutonic rocks formed as part of the active Permian Gondwana margin (ca. 280-260 Ma). Whilst two samples record their original Permian age, two other samples yield cretaceous ages (~100 Ma), consistent with regional magmatic activity during the breakup of Gondwana. Two samples with mixed populations of micas confirmed a partial reset in this rock, and thereby the full reset for the Cretaceous ages. An intriguing aspect is that reset is predominant in spot analyses with higher Rb/Sr, making these sections apparently more prone to thermal reset, likely through higher diffusion potentials. We interpret the resetting of the system as a response to thermal perturbation of the igneous rocks with no apparent petrographic footprint. It is demonstrated that in-situ Rb-Sr dating of igneous micas in plutons can be used to date magmatic flare-ups in rocks that can be hundreds of millions of tears older. The technique thus holds immense potential to decipher the thermal histories of terranes that otherwise remain undetected and may be used to shed new light on a large number of suspect Rb-Sr (mixed?) ages with no apparent geologic meaning.
Sulfate formation in haze pollution using multiple sulfur isotopes
Authors: Guo Qingjun , Han Xiaokun , Dong Xinyuan , Qin Xuechao , Wei Rongfei
Published: March 2024

Air pollution has become a serious problem in some parts of the world. The mechanism of sulfate formation during haze events is still not clear. This research looks at the different sulfur isotope compositions of sulfate in PM2.5 (from 2015 to 2016) in Beijing and in seasonal samples of PM2.5, PM1.0, and TSP from rural, suburban, urban, industrial, and coastal areas of North China (in 2017). The goal is to figure out the mechanism by which SO2 oxidizes at different levels of air pollution. An obvious seasonal variation (with positive values in spring, summer, and autumn and negative values in winter) is shown by the Δ33S values of sulfate in aerosols, except for those samples collected in rural areas. The Δ33S value (S-MIF) of sulfate in PM2.5 shows a pronounced seasonality, with positive values in spring, summer, and autumn and negative values in winter. The negative Δ33S changes that happen during winter haze events are mostly caused by SO2 being oxidized by H2O2 and transition metal ion catalysis (TMI) in the troposphere, which is most likely caused by coal burning. The positive Δ33S results observed on clean days are mainly attributed to tropospheric SO2 oxidation and stratospheric SO2 photolysis. These results provide important information on sulfate formation during haze events and clean days.
Satellite unravels recent changes in atmospheric nitrogen oxides emissions from global ocean shipping
Authors: Wang Xiaohan , Zhang Chengxin , Liu Cheng
Published: March 2024

Nitrogen dioxide (NO2) in the lower marine atmosphere, mainly emitted by maritime shipping, plays a crucial role in air pollution formation and global human health. However, few measurements of marine atmospheric NO2 hinder knowledge of trace gas trends and atmospheric chemistry evolution due to shipping emissions. In this study, we use long-term satellite observations of tropospheric NO2 column from the European TROPOspheric Monitoring Instrument (TROPOMI) and the Chinese Environmental trace gases Monitoring Instrument (EMI) to analyze marine atmospheric NO2 variations, especially during the global COVID-19 pandemic and escalating geopolitical crises. First, we demonstrate the detection of NO2 enhancements along shipping routes, including the North Atlantic route, the North Pacific route, and the Cape route, indicating significant emissions of atmospheric NO2 from on-ocean shipping. Second, we observe and quantify the response of marine atmospheric NO2 concentrations to major shipping events, such as the Suez Canal blockage, the Los Angeles-Long Beach port congestion, and the Russia-Ukraine war, resulting in local NO2 concentration variations of approximately 40% decrease to 70% increase. Long-term analysis reveals reduced NO2 concentrations in most coastal ports and maritime shipping routes during the COVID-19 lockdown, with reductions exceeding 50% or durations lasting up to 200 days. However, some rapidly developing ports, such as Beibu Gulf (China) and Dakar (Senegal), did not experience a decrease in NO2 concentrations, suggesting that local authorities need to pay more attention to these fast-growing yet underestimated emission sources. In addition, by excluding the impact of meteorology using statistical models, we find that the current Emission Control Area (ECA) policies have effectively reduced NO2 concentrations in Chinese coastal ports. These results contribute to understanding spatiotemporal characteristics of marine atmospheric NO2, including ports and open-sea shipping routes, and guide further ECA policies to control marine NO2 pollution.
Highly consistent brightness temperature fundamental climate data record from SSM/I and SSMIS
Authors: Liu Shi , Wang Yu
Published: March 2024

A multi-channel brightness temperature (TB) Fundamental Climate Data Record (FCDR) for the period 1991-present has been developed in this study using measurements from two Special Sensor Microwave Imagers (SSM/I) onboard the F11 and F13 satellites and one Special Sensor Microwave Imager/Sounder (SSMIS) onboard the F17 satellite of the US Defense Meteorological Satellite Program (DMSP). Hardware differences among these instruments were corrected using a combination of techniques including Principal Component Analysis (PCA), using the third instrument as an intermediate, and weighted averaging, which accounts for interchannel covariability and observation matching issues. After intercalibration, all imagers were standardized using SSMIS as the observation reference. The average biases of the recalibrated TBs for almost all channels between any two instruments are globally less than 0.2 K, with standard deviations (STDs) of less than 1.2 K. This resulted in a 30-year continuous and stable FCDR. Based on this FCDR, a long time series of column water vapour (CWV) over the global oceans was retrieved. Validation of this retrieved moisture product against reanalysis, in-situ radiosonde, and Global Navigation Satellite System (GNSS) measurements showed reasonable accuracy, suggesting that the presented FCDR has high potential for climate applications. In the future, this research method will be applied to more satellites to create an expanding dataset of satellite observations that could enhance the accuracy of climate model assessments and improve the reliability of climate predictions.
Magnitudes, patterns, controls and mitigation potentials of nitrous oxide emissions across peatlands in Europe
Authors: Ma Lei , Gan Dezhao , Wang Jinsong , Niu Shuli
Published: March 2024

European natural peatlands have undergone long-term anthropogenic drainage activities that have severely decreased their functions, such as carbon sequestration. Recent rewetting has been conducted to restore the ecosystem services of peatlands and mitigate the emissions of potent greenhouse gases such as nitrous oxide (N2O). However, the magnitudes and spatial patterns of annual N2O fluxes and their mitigation potentials across European peatlands remain unknown. Here, we synthesized 492 annual N2O flux data points from 77 in situ studies across European peatlands and found that the soil annual N2O fluxes varied extensively from -1.08 to 33.40 kg N2O-N ha-1 yr-1; these results were significantly and interactively (P < 0.05) affected by the peatland status, climatic regime and nutrient supply type. Drainage significantly (P < 0.05) stimulated soil N2O emissions from natural minerotrophic rather than ombrotrophic peatlands, regardless of the climatic regime. Similarly, rewetting significantly (P < 0.05) reduced soil N2O emissions from drained minerotrophic rather than ombrotrophic peatlands, demonstrating that the high N2O emissions were driven by a simultaneous decline in the water table depth and increase in the soil nitrogen (N) availability. Magnitudes of the increases or decreases in N2O emissions due to drainage or rewetting were also significantly influenced by the land-use and drainage history before rewetting and in the years following drainage/rewetting, respectively. The estimated annual mean N2O emission total was found to be 90.42 (95% confidence interval: 64.49-122.57) Gg N2O-N in 2020 from European peatlands. Scenario analysis showed that drained peatlands should be rewetted expeditiously; postponing rewetting would cause larger emissions from continued N2O emissions from drained peatlands. Fully rewetting the drained peatlands used for forestry and peat extraction and partially rewetting those used for agriculture and grassland comprise a strategy for mitigating drained peatland N2O emissions without compromising food security.
On the connection between eddy impingement east of Taiwan and Kuroshio intrusion into South China Sea
Authors: Tseng Yu-Hao , Ho Chung-Ru
Published: March 2024

Using absolute dynamic topography and satellite altimeter eddy tracking data, the intrusion of the Kuroshio caused by the impingement of mesoscale cyclone eddies east of Taiwan into the northern South China Sea (NSCS) through the Luzon Strait was studied. Between 1993 and 2021, a total of 12 such cases were identified. Six of them occurred when the Kuroshio upstream (east of Luzon) strengthened and the Kuroshio downstream (east of Taiwan) weakened. A composite analysis of all cases shows that the average time from when a mesoscale cyclonic eddy impinges the Kuroshio east of Taiwan to when the NSCS reaches maximum negative vorticity is about 28 days. When the Kuroshio upstream strengthens and downstream weakens, the negative vorticity of the NSCS west of the Luzon Strait increases by 45% compared with normal conditions. The duration of the interaction between the Kuroshio and the mesoscale cyclonic eddy east of Taiwan is 28 days, compared with the normal 41 days.
Source, enrichment and risk assessment of atmospheric aerosols (PM10) at urban/industrial city, Hyderabad, India
Authors: Attri Pradeep , Mani Devleena
Published: March 2024

A long-term study (2019-2021) to understand the chemical characteristics of atmospheric aerosols (PM10), collected fortnightly on quartz fibre filters in an urban/industrial location of Hyderabad, India was carried out by measuring the trace, rare earth and heavy elements, water-soluble inorganic ions and carbon isotopes. High K+nss/OC was observed during post-monsoon and winter, suggesting contribution from local and biomass/crop residue burning from surrounding regions. Cr, Mo, Cs, Ce and Pb were observed to be 22%, 88%, 92%, 20% and 18% higher than WHO's daily and annual limit. The role of transition elements, mainly Fe and Mn, in catalysing HO2- or O2- and converting them to H2O2 and H2O, respectively was explored, where Cu/Fe (annual average: 0.02 ± 0.01) and Cu/Mn (0.24 ± 0.15) ratios suggested the dominance of H2O regime compared to H2O2 regime. The enrichment factor (EF) of trace and heavy metals were mostly in the range of 10 < EF < 100 (Fe ref ) and 1 < EF < 10 (Ti ref). Enrichment of Ba and Se during post-monsoon, Sb and Cr during post-monsoon 2019 and winter 2020 and Co during summer were observed. The stable carbon isotopes of TC (δ13CTC) and EC (δ13CEC) varied from - 28.1 to - 24.7 ‰ (avg. - 26.5 ± 0.7) and - 32.5 to - 24.6 ‰ (avg. - 27.4 ± 1.1), indicating contribution from C3 plant burning and liquid fuel combustion (vehicular exhausts). Positive value of δ13COC - δ13CEC and heavier δ13CTC, along with gradual enrichment in δ13CTC and δ13CEC from December 2020 to March 2021, implied the photochemical aging of CA. Lighter δ13CTOC and OC/EC > 4 for all seasons suggest the dominance of biomass burning (wood and crop residue burning), photochemical oxidation and SOA formation.Further, the inhalation risk on human health during exposure to harmful metals was investigated for entire sampling duration, and the dominance of sources for carcinogenic Cd at the sampling location were inferred compared to electronic-plastic waste-burning sources (eg Sn). La, Ce, V, Mo, Cs and Rb were observed to be from continental crust sources, considering their common sources. Carcinogenic inhalation risk for Cr(VI) was only observed during post-monsoon 2019, and non-carcinogenic inhalation risk (hazard index >1) was observed throughout the sampling duration for all considered metals was observed.