bluuebunny/crossref_metadata_2025 huggingface dataset:
Unveiling urban atmospheres: a comprehensive study on CO2 dynamics, air quality, and volcanic impacts in Napoli and Pozzuoli
Authors: Di Martino Roberto , Gurrieri Sergio , Paonita Antonio , Caliro Stefano , Santi Alessandro
Published: March 2024

The atmospheric concentration of CO2 is crucial in urban areas due to its connection with air quality, pollution, and climate change. Monitoring airborne CO2 concentrations is vital for environmental management and public safety.  In the lower 50 meters of the atmosphere, CO2 emissions impact human health and ecosystems, making data at this level essential for addressing carbon-cycle and public-health questions. In volcanic zones, CO2 variations may correlate with volcanic activity, impacting local ecosystems and human health. In certain regions with high natural CO2 emissions, geogenic CO2 profoundly affects the environment. Despite volcanoes' local impact may be important, hydrocarbon combustion is the primary driver of increased atmospheric CO2 and global warming climate.This study presents survey results on stable isotope composition of carbon and oxygen of CO2 and airborne CO2 concentration in the Campi Flegrei caldera, a high volcanic risk area threatening the Naples metropolitan area. In the last 50 years, two major volcanic unrests (1969–72 and 1982–84) were monitored using seismic, deformation, and geochemical data. The current unrest started in 2005, involving pressurization of the underlying hydrothermal system as a causal factor of the current uplift in the Pozzuoli area.This research illustrates the use of a mobile laboratory to better understand emissions dynamics and quantify volcanic-origin emissions. Results shows that CO2 levels in Napoli's urban area exceed background atmosphere levels, indicating an anthropogenic origin from fossil fuel combustion. Conversely, in Pozzuoli's urban area, the stable isotope composition reveals a volcanic origin of the airborne CO2. This study demonstrates how a spatial survey of stable isotope composition of airborne CO2 is crucial for understanding emission dynamics. Distinguishing geogenic from anthropogenic emissions is challenging, especially through air CO2 concentration measurements alone. The findings emphasize the importance of monitoring atmospheric CO2, especially in areas with volcanic risks, contributing valuable insights for environmental and public health management.
Uppermost mantle radial anisotropy based on double-beamforming of ambient noise cross correlation beneath Iranian plateau
Authors: Movaghari Ramin , Yang Yingjie
Published: March 2024

The continental lithosphere of the Iranian plateau is complicated by a multitude of tectonic processes resulting from the convergence between the Arabian and Eurasian plates. In order to investigate the deformation mechanisms of the uppermost mantle, this study presents a radial anisotropy model beneath the Iranian Plateau constructed by long period (10-100 s) Rayleigh and Love waves from ambient noise data. The broadband Rayleigh and Love signals are extracted from continuous data recorded by 88 seismic stations using a double-beamforming algorithm. Due to utilizing long period surface waves, we apply finite-frequency ambient noise tomography to generate two-dimensional dispersion maps. These phase velocity maps are consistent with those obtained from conventional methods. Finally, we invert Rayleigh and Love local phase velocity dispersion curves using a Bayesian Markov chain Monte Carlo inversion method. The obtained radial anisotropy model shows negative values in Central Iran suggesting a horizontal character of the minerals likely due to a channelized asthenospheric flow in the upper mantle.
Summer and tropical consecutive days in normal periods 1961-1990 and 1991-2020.
Authors: Faško Pavel , Bochníček Oliver , Markovič Ladislav
Published: March 2024

Summer and tropical days were and are part of the processing of historical observations. Their processing was the content of each monthly report of meteorological observations as well as the annual processing in the form of a yearbook. Changes in temperature (especially positive deviations from normal values) also cause their more frequent occurrence. This would not be unusual or unexpected, even if the regularity of these periods cannot be predicted. Higher air temperatures often cause health problems, especially for older and more sensitive people. Nausea and loss of concentration occur especially during longer periods of hot days. In this contribution, we decided to process the occurrence of periods of summer days (t_max≥25 °C) and periods of tropical days (t_max≥30 °C). The term period here means consecutive days (minimum 2). Professional and aerial meteorological stations covering the territory of Slovakia well were selected. Their length was considered for two normal periods, namely 1961-1990 and 1991 - 2020. The mutual comparison gave us a clear idea of the redistribution of periods of different lengths and the territorial unit (places in Slovakia). While for summer days we observe a decrease in shorter periods and an increase in longer periods, especially in lowland areas, in the rest of the territory, especially in the north, or in mountainous areas, rather an increase even from the shortest periods.On tropical days, or when comparing the periods of tropical days in both normal periods (1961 - 1990 and 1991 - 2020), we find the fact of a very strong increase from the shortest periods of consecutive tropical days at all selected meteorological stations. Since it is impossible to compare the frequency of periods as well as the number of tropical days themselves in absolute terms, we helped ourselves with a percentage evaluation. The fact is that, especially for tropical days, the biggest increase is in the north of the country, the shortest periods (2-3 days in a row) increased by up to 250%. They even began to appear in places where they could not be observed in the period 1961 - 1990. The results conceived in this way will help not only the tourism industry, but also the adaptation of man and his environment to changes in the climate system. 
Significant Impacts of El Niño-Southern Oscillation and Indian Ocean Dipole on China’s Gross Primary Production
Authors: Yan Ran , Wang Jun , Ju Weimin , Wang Xunmei , Tan Jingye
Published: March 2024

Gross primary production (GPP) stands as a crucial component in the terrestrial carbon cycle, greatly affected by large-scale circulation adjustments. This study investigates the influence of El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) on China’s GPP, utilizing long-term GPP data simulated by the Boreal Ecosystem Productivity Simulator (BEPS). Partial correlation coefficients between GPP and ENSO reveal substantial negative associations in most parts of western and northern China during September-October-November (SON). These correlations shift to strongly positive over southern China in December-January-February (DJF), then weaken in March-April-May (MAM), eventually turning generally negative over southwestern and northeastern China in June-July-August (JJA). In contrast, the relationship between GPP and IOD basically exhibits opposite patterns. Composite analysis further confirms these seasonal GPP anomalous patterns. Mechanistically, we ascertain that, in general, these variations are predominantly controlled by soil moisture in SON and JJA, but temperature in DJF and MAM. Quantitatively, China's annual GPP demonstrates modest positive anomalies in La Niña and nIOD years, in contrast to minor negative anomalies in El Niño and pIOD years. This results from counterbalancing effects with significantly greater GPP anomalous magnitudes in DJF and JJA. Additionally, the relative changes in total GPP anomalies at the provincial scale display an east-west pattern in annual variation, while the influence of IOD events on GPP presents an opposing north-south pattern. We believe that this study can significantly contribute to our comprehension of how intricate atmospheric dynamics influence China’s GPP on an interannual scale.
Disentangling forced trends in the North Atlantic jet in CESM2 using deep learning 
Authors: Hermoso Alejandro , Schemm Sebastian
Published: March 2024

According to state-of-the-art climate simulations, the future evolution of the wintertime North Atlantic jet stream is highly uncertain compared to other ocean basins. This has important consequences on the projected daily weather variability and the occurrence of extreme events over Europe. In this context, disentangling the forced trends in the North Atlantic jet caused by an increase in greenhouse gases from its natural variability is a challenging but extremely relevant task.In this study, we use a deep learning-based method, the Latent Linear Adjustment Autoencoder (LLAE), to separate forced trends from natural variability in an ensemble of fully-coupled Community Earth System Model simulations. The LLAE consists of a variational autoencoder and an additional linear component. The model predicts the component of the wind associated with natural variability from upper-level detrended temperature and geopotential. The residual between this prediction and the original wind field can be interpreted as the component of the wind related to the external forcing. Despite the large variability of the original trends, especially in the historical period, the LLAE is effective in extracting the forced component of the trend, which is similar for all ensemble members. The main characteristics of the forced trend are an increase in the wind speed along a southwest-northeast oriented band and an extension of the jet over Europe. These features are common for different periods and have similarities to the full North Atlantic jet trend in the ERA5 reanalysis.
Hydrogeological Study and Tracing of Groundwater Flow Paths in the Beinan River Basin within Eastern Taiwan's Alpine Catchment
Authors: Lee Yu Hsuan , Chiu Yung Chia
Published: March 2024

The growing demand for water resources is exacerbated by the impacts of climate variations, uneven rainfall distribution, and population growth. In the global inventory of water resources, rivers in mountainous regions contribute significantly to the available water supply. The subsurface aquifer system in these mountainous watersheds plays a crucial role in the hydrological cycle, serving not only as a primary source for downstream rivers or aquifers but also as a vital replenishment source during periods of drought. Due to its remote location and limited manpower, a comprehensive understanding of the hydrological functions of groundwater within the mountain system remains a challenge. Accordingly, this study selected the alpine watershed of Beinan River in eastern Taiwan, characterized by minimal human activities, to delineate groundwater flow paths and evaluate potential contribution of groundwater to water resources to address the existing gaps in understanding. Through long-term streamflow and groundwater level analyses combined with hydraulic tests and tracer experiments, the objective of this study focuses on delineating the subsurface flow paths from weathered soils and regolith to fractured bedrock and characterizing their associated hydraulic properties in this alpine hydrogeological setting. The results show that the main contributor to streamflow is shallow groundwater, particularly during the dry season. Rainfall infiltration is primarily observed in the weathered soils and regolith manifesting as the mountain front recharge (MFR). The groundwater flow in the bedrock is predominated influence by the fractures and its sources can be traced back to distant hillslopes. The water budget within the entire alpine system is preliminary quantified based on the long-term data and hydraulic parameters obtained from the field tests. The results obtained in this study can provide as a reference for developing conceptual models and fundamental frameworks for quantifying the water budget in alpine environments.Keywords: alpine hydrogeology, groundwater flow path, fractured flow, water budget, Taiwan 
Crustal structures and Cenozoic magmatism in the northwestern South China Sea
Authors: Gao Jinwei , Lüdmann Thomas , Li Chun-Feng , Li Lin , Tian Liyan , Qin Yongpeng , Song Taoran
Published: March 2024

This study investigates the crustal structure and Cenozoic magmatism in the northwestern South China Sea (SCS), based on the long-cable multi-channel seismic reflection profiles, together with gravity and magnetic data, and adjacent wide-angle refraction profiles. Basins/sags are bounded by large listricnormal faults (fault throws ≥ 0.5 km) and massifs are cut off by normal faults with small offsets (fault throws < 0.5 km) in the northwestern SCS. These structures are penetrated by magmatic edifices showing positive gravity and magnetic anomalies. Syn-rift magmatic intrusions/extrusions were intense in the basins/sags and continent-ocean transition zone while post-rift magmatism was widespread from basins/sags to massifs with the most intense stage occurring from 5.5 to 2.6 Ma. Based on previous geophysical and geochemical results, we suggest that syn-rift mantle upwelling from partial melting initiated seafloor spreading magmatic activities, whereas plume-related mantle upwelling contributed to the magmatism during and after seafloor spreading in the northwestern SCS. Stretching factors show that the upper and lower crusts have experienced differential extension from basins/sags to massifs. The nonuniform crustal extension resulted from upper crustal faulting and lower crustal flow. Particularly, the lower crustal flow was probably linked with the combined action of magmatic heating, mantle flow shearing stresses, and sediment loading, resulting in crustal boudinage and reestablishment of an equilibrium state over long distances.
Predicting Flash Droughts Using Transformers: Understanding Surface and Root Zone 
Authors: Chang-Silva Roberto , Park Seonyoung
Published: March 2024

Flash droughts, characterized by their rapid onset and devastating agricultural and ecological impacts, pose a growing threat in a changing climate. Accurate and timely predictions are crucial for implementing mitigation strategies and minimizing their widespread consequences. This research presents a novel transformer-based forecasting system designed to predict soil moisture with a focus on detecting the early warning signs of flash droughts in North America. This study integrates the concepts of the two main soil moisture zones, surface and root zones, to provide a comprehensive understanding of drought dynamics. The research leverages the NLDAS (North American Land Data Assimilation System) simulation dataset, offering high-resolution spatiotemporal information crucial for accurate modeling. The transformer-based architecture is employed to capture complex temporal dependencies and non-linear relationships inherent in soil moisture variations. The architecture captures long-range dependencies and complex interrelations within the data, enabling accurate predictions of both surface and root zone moisture content. This approach enables the development of a robust forecasting model capable of capturing sudden and intense decreases in soil moisture characteristic of flash droughts. The system considers the relationship between surface and root zone soil moisture, acknowledging their distinct roles in impacting vegetation health, water availability, and overall ecosystem resilience. By incorporating this dual-zone perspective, the forecasting system enhances the accuracy of flash drought predictions, providing valuable insights for early intervention and adaptive management. Through rigorous evaluations and comparisons with existing forecasting methods, we assess the system's performance in capturing spatiotemporal variability and providing lead time for proactive mitigation strategies. Our findings shed light on the transformative potential of deep learning for flash drought prediction, highlighting the crucial role of understanding the interplay between surface and root zone moisture dynamics in this context.
Implementing Nature-Based Solutions in the urban environment: benefits, limitations, and future challenges 
Authors: Cristiano Elena
Published: March 2024

According to the United Nations projections, the global population is expected to continuously grow in the next years, reaching 9.7 billion by 2050, and more than 70% of it will live in cities, with a consequent intensification of urbanization. In this context, the increase of short but intense rainfall events, as foreseen by the Intergovernmental Panel on Climate Change for many geographical regions, will lead to an increment of pluvial floods in urban areas, due to a higher and faster runoff generation. Besides a more traditional approach, where the sewer system is simply updated with larger pipes, multiple nature-based solutions, also called blue-green solutions, have been proposed and implemented to mitigate the runoff generation from impervious surfaces. These innovative solutions aim to reintroduce natural elements in the urbanized areas, and benefit from the soil retention capacity to store water during intense rainfall events and release it in the environment via evaporation, evapotranspiration, and infiltration processes. With the installation of these solutions, the volume of water collected by the drainage system is limited and, consequently, the pluvial flood risk is reduced. Among the most common nature-based solutions, it is worth recalling green roofs, green walls, rain gardens and retention and detention basins, which guarantee multiple benefits for the urban environment. Besides the runoff reduction, these structures can, in fact, help lowering the average temperatures, limiting the generation of the urban heat island, they improve the air quality, facilitating the CO2 sequestration, they increase the biodiversity, and they add aesthetic value to the cities, supporting the citizens’ physical and mental health. In this framework, this work presents a review of the most common and efficient nature-based solutions, installed in cities to mitigate pluvial floods and to ensure a sustainable development of the urban environment. Several nature-based solutions have proposed to mitigate pluvial floods and have shown high potential at local scale, while a large scale, involving the entire city, needs to be further investigated. Moreover, the integration of different blue-green solutions in the urban environment should receive further attentions to enhance the creation of smart and resilient cities.
The role of stratospheric processes in the trans-seasonal connection between spring and summer northern annular modes
Authors: Xu Xiran , Wang Lei , Wang Tao , Chen Gang
Published: March 2024

The summer northern annular mode (NAM) variability plays a crucial role in the summer climate variability and extremes of the Northern Hemisphere. In this study, we report a significant negative correlation between the March NAM and summer NAM during 1979–2022 and reveal the role of the spring stratosphere in this seasonal linkage. Particularly, it is found that the negative phase of March NAM features a strong meridional shear in the extended-North-Atlantic jet, which tends to generate planetary scale Rossby waves that propagate upward and poleward into the stratosphere. This increased stratospheric planetary wave activity in March transitions to weakened wave activity in May, leading to positive zonal wind anomalies in the polar stratosphere in May, extending downward to the troposphere in June and promoting the formation and persistence of positive summer NAM. The results provide both statistical and dynamical evidence for the role of the spring stratosphere in connecting the spring and summer circulation. 
Decoding Cenozoic climate variability: dominant timescales beyond critical transitions
Authors: Alberti Tommaso , Florindo Fabio , Rohling Eelco J. , Lucarini Valerio , Faranda Davide
Published: March 2024

While previous climate transitions are easily identifiable, a comprehensive understanding of their underlying mechanisms and timescales remains elusive. In this investigation, we employ dimensional analysis of benthic stable isotope records to unveil the associations between climatic fluctuations in the Cenozoic era and changes in the number of effective degrees of freedom across various timescales. The Hothouse and Warmhouse states are predominantly influenced by precession timescales, whereas the Icehouse climate is primarily shaped by obliquity and eccentricity timescales. Remarkably, the Coolhouse state lacks distinct dominant timescales. Our analytical approach effectively identifies abrupt climate shifts and extremes objectively, as evidenced by high-resolution data from the last glacial cycle, which reveals sudden climate shifts within a single climate state. These findings have profound implications for our comprehension of the inherent stability of each climate state and the assessment of (paleo-)climate models' ability to accurately replicate crucial features of past and future climate states and transitions.
Climate change and Cosmography 
Authors: Vagenas Athanasios
Published: March 2024

CLIMATE CHANGE AND COSMOGRAPHY IntroductionA beautiful universe, with the small earth at its center mediating knowledge and carrying it everywhere. From schools, universities and science museums. In our museum this year, the theme of our museum is extantas and cosmography in general. In addition, climate change has unexpectedly arisen, following the heavy rainfall that characterizes our planet and especially our region (Mouzaki-Karditsas 2019).https://kpem.gr/kyrio/mm/mm.htmlMany times there are events that outweigh our personal promote and require collective efforts to get better results. Our school is directly connected to our society, because our students live in it almost all day long. Their concerns are our concerns. Thus, in the events that occurred in the Municipality of Karditsa and the Municipality of Mouzaki concerning the floods, as a school with published educational activities we will give the historical and social dimension of the problem. Our pedagogical approach is intended as another message to be a reminder of the mechanisms that can help our region. Students exhibit their photographic material.Climate change. Recent Historical Document It is very important, especially after the continuous disasters in recent years in Greece, neighboring countries and around the world caused by floods. It is also important in planning related to the environmental management of water resources and as applications of ecological engineering, which is necessary for our region and our country in general.The effects of global warming are not evenly distributed over all latitudes and longitudes. Climatic phenomena such as droughts, floods are expected to occur more frequently. The picture I encounter on the way to my school where, farms still have water, plants muddy is nightmarish. The Headmaster of the school on the morning calling after a week of suspension only asked who has no books due to water ingress at home. There are rumors of students who have lost their homes. After the second week was over we began to discuss the damage everyone has suffered, and it is normal to have lost part of your home, furniture and clothing.Social dimension of the European project OSOS (Open Schools for open Societies)Everything that is happening today should end quickly. The school to find its normal rhythm. The idea of OSOS has entered our lives as a basic tool and not as an accumulated knowledge or as an interactive tool for solving exercises in various forums. That is how we will try to continue our coursework. To approach the physical teaching of the classroom with complementary activities outside of it. So we too offer interactively as a classroom group, as a school and as a science museum to our local community, to worry to hope for something better.Five years later 2023 in the region of Trikala, Farkadona and Karditsa(Palamas) exactly the same flooding events occur. The photographic material describes IANOS and DANIEL.The OSOS logo contained in four words captures a new vision for schools : Feel - Imagine - Create - Share.  Thank you
Subseasonal Modes of Winter Surface Air Temperature in Eurasia's Mid- and High-Latitudes: Contributions from the North Atlantic and Arctic Regions
Authors: Li Shiyue , Hu Haibo , Ren Xuejuan
Published: March 2024

A significant and striking seesaw pattern of winter surface air temperature (SAT) has emerged, featuring pronounced warming Arctic and cooling Eurasian (referred to as WACE). This study investigates the subseasonal SAT modes across the mid- and high-latitudes of Eurasia and their possible mechanisms based on daily reanalysis data from 1979 to 2022. Our results reveal that Eurasian winter SAT exhibits two distinct subseasonal modes, characterized by a correlated southeastward propagation of temperature and geopotential height anomalies (GHAs) in the middle and lower troposphere. Notably, 8 phases of the subseasonal SAT modes are identified to form a comprehensive life cycle from the Arctic to East Asia. The sixth phase of the subseasonal SAT modes is proved to be the key transition phase from the WACE pattern to its counterpart. Further analysis indicates that the subseasonal tropospheric potential height anomalies over the Arctic are determined by the anomalies of stratospheric potential height and the surface turbulent heat fluxes anomalies in the north Atlantic.
Benefits for the terrestrial reference frame with VLBI observations to Genesis
Authors: Böhm Johannes , Wolf Helene , Kern Lisa
Published: March 2024

Mission Genesis of the European Space Agency (ESA) has been approved for launch in 2027. Genesis will be the first satellite in orbit to have a dedicated Very Long Baseline Interferometry (VLBI) transmitter on board, next to Global Navigation Satellite System (GNSS) and Doppler Orbitography and Radiopositioning Integrated on Satellite (DORIS) receivers as well as a Satellite Laser Ranging (SLR) reflector; consequently, Genesis will realize a space tie combining all geometric space geodetic techniques. If perfectly calibrated, the space tie will enhance and improve local ties measured on the ground. The following scenario is possible: If the orbit of Genesis is determined from the satellite techniques alone, the station coordinates of the VLBI radio telescopes in the "satellite frame" can be derived by VLBI observations to Genesis, thereby assessing the tie with the "VLBI frame", realized with decades of VLBI observations to quasars.We present our plans to devise observing strategies for VLBI to reach accuracies as defined in the Genesis white paper. We start with our findings for VLBI transmitters on Galileo satellites, before we show the simulation results for the VLBI transmitter on Genesis. We illustrate the advantages of the Genesis satellite at 6000 km altitude compared to Galileo satellites in terms of sky coverage and accuracy of station coordinates, but also in terms of orbit estimation. Furthermore, we provide an outlook on geodetic parameters, which could not be determined with VLBI so far but will be possible with Genesis.
The benefits of distributed grid production: An insight on the role of spatial scale on solar PV energy
Authors: Chatzopoulos Dimitrios , Zisos Athanasios , Mamassis Nikos , Efstratiadis Andreas
Published: March 2024

The hydrometeorological processes associated with renewables are characterized by substantial spatiotemporal variability, and thus uncertainty, which is addressed through decentralized planning, thus taking advantage of scaling effects. The objective of this work is to provide a comprehensive investigation of the role of scale regarding solar photovoltaic production in Greece, which is one of the predominant renewables. By implementing macroscopic criteria in terms of solar potential (e.g., topography-adjusted radiation indices), we select a sufficient sample of well-distributed locations in Greece. For these points, hourly radiation and temperature data, derived from satellite products, are retrieved and validated against ground observations. Following this, we formulate a detailed simulation procedure that accounts for the two physical drivers and the panel characteristics (i.e., efficiency and temperature impacts due to heating), and we configure the baseline scenario by computing the individual production of each site. Next, to highlight the added value of distributed production and quantify the scaling effects in PV power production, we follow a Monte Carlo approach by randomly distributing PVs across the selected locations, to eventually provide a statistical analysis on the spatial and temporal domain and over different PV technologies.
Evaluation of continuously recorded fractional bedload transport rates in Swiss mountain streams
Authors: Baldig Danny , Rickenmann Dieter
Published: March 2024

In mountainous regions, the dynamics of bedload transport can vary considerably, including significant changes over brief periods, thus also posing a substantial challenge for bedload transport measurement and prediction. Indirect monitoring systems like the Swiss Plate Geophone (SPG) have led to a significant advancement in our capacity to continuously monitor bedload processes (Rickenmann, 2017). Based on recording important parts of the raw measuring signal of the SPG system, we have developed a procedure to determine fractional bedload transport rates (Wyss et al., 2016; Nicollier et al., 2022). For this, each sediment collision (for particles larger than 9.5mm) is recorded with the SPG system as a discrete «packet», capturing raw signal information such as collision start and end times, raw and envelope amplitude, squared integral, and centroid frequency of the raw signal.
This research undertakes a detailed analysis of continuously recorded packet data from the SPG for several mountain streams in Switzerland. It aims to quantify fractional bedload transport rates and grain size distribution across various periods. To check the plausibility of the calculated fractional transport rates, we aggregated the data based on the packet analysis and compared it to the so-called «impulse-based» conversion of the SPG signal into total transport rates (independent of grain size classes). The objective of this study is to enhance the understanding of how grain size distribution of the bedload alters with changing discharge and bedload transport conditions, by considering different channel characteristics and evaluation periods.
 
References
Nicollier, T., Antoniazza, G., Ammann, L., Rickenmann, D., and Kirchner, J. W.: Toward a general calibration of the Swiss plate geophone system for fractional bedload transport, Earth Surf. Dynam., 10, 929–951, https://doi.org/10.5194/esurf-10-929-2022, 2022.
Rickenmann, D.: Bed-load transport measurements with geophones and other passive acoustic methods, J. Hydraul. Eng., 143, 03117004-1-14, https://doi.org/10.1061/(ASCE)HY.1943-7900.0001300, 2017.
Wyss, C. R., Rickenmann, D., Fritschi, B., Turowski, J.,Weitbrecht, V., and Boes, R.: Measuring bed load transport rates by grain-size fraction using the Swiss plate geophone signal at the Erlenbach, J. Hydraul. Eng., 142, https://doi.org/10.1061/(ASCE)HY.1943-7900.0001090,04016003, 2016.
Artifacts in muon-tomography
Authors: Balázs László , Szűcs József Gábor , Rabóczki Bence , Stefán Boglárka Abigél , Nyitrai Gábor , Surányi Gergely , Hamar Gergő , Oláh László , Varga Dezső
Published: March 2024

Muon-tomography is a rapidly evolving technique whis is widely and increasingly used in geology, geotechnics, and archaeology.The method provides an approximate 3D density distribution of the object under investigation (scanned), which is inherently loaded with artifacts. The analysis of the artifacts is essential for the interpretation and post-processing of the tomographic image, allowing the highlighting of the real density anomaly regions.In the poster presentation, the structure and characteristics of the artifacts will be analysed, depending on whether the source of the artifact is a real anomaly, measurement noise, side effect or perhaps an insufficiently accurate consideration of the topography. The anomaly contrast distortion effect of muographic mapping is also analysed. The results are illustrated with simulated and real measurement anomalies. The poster presentation will also cover the possibility of suppressing artifacts. The applicable procedures depend on the method of parameter discretization (voxelization) and the angular resolution of the muographic measurements recorded in different positions, but the applied regularization of the inversion procedure is the key factor in our study. In the presentation, results of parameter studies on these issues will be presented.
Using MONICA model to investigate the water, carbon, and nitrogen dynamics in wet grasslands for future rewetting plans.
Authors: Khaledi Valeh , Baatz Roland , Antonijević Danica , Hoffmann Mathias , Dietrich Ottfried , Lischeid Gunnar , Davies Mariel F , Merz Christoph , Nendel Claas
Published: March 2024

IntroductionWet grassland sites have accumulated large amounts of carbon in their soil over millennia. While under excessive drainage and intensive agriculture, these sites have shown substantial losses of the stored carbon to the atmosphere, the current climate mitigation strategies see a conversion of this process through rewetting. Situated in the fringe of ascending groundwater, these sites respond very sensitively to changes in the water table, both in the vegetation and the turn-over processes in the soil. While researchers have extensively investigated how wet grasslands respond to changes in environmental conditions or management practices from various perspectives, there is a lack of a comprehensive simultaneous study addressing the intricate interplay of water, carbon, and nitrogen cycles in these ecosystems. This study aimed at addressing the water, carbon, and nitrogen dynamics in a wet grassland site using a process-based agroecosystem model to prepare the model for future scenario simulations under various options for rewetting.Material and methodThe study site is situated in the Spreewald wetlands, where a lysimeter station featuring four lysimeters with different groundwater level management practices has been installed. Within the lysimeter station, a weather station records the meteorological conditions. Above-ground biomass is measured after each cut, and various parameters including evapotranspiration, gross primary productivity, ecosystem respiration, nitrogen amount in biomass, nitrate leaching, and N2O are monitored. The process-based model employed in this study is the MONICA model (Model for Nitrogen and Carbon in Agro-ecosystems). The SPOTPY algorithm was used for optimising the model.ResultsPresented in three categories are the results: firstly, evapotranspiration as a vital component of the water cycle; followed by gross primary productivity and ecosystem respiration, offering insights into the carbon cycle. Additionally, nitrogen content in biomass, nitrate leachate, and N2O are examined, providing information related to the nitrogen balance.Within a wet grassland ecosystem, MONICA has effectively reproduced these essential variables, showcasing remarkable performance with rRMSE ranging between 0.05 to 0.81, and Willmott’s Refined Index of Agreement dr ≥ 0.3 in all cases. This substantiates its capability to simulate the impacts of environmental or management changes, particularly those associated with modifications in surface-near groundwater conditions. The model's robust replication of crucial variables emphasizes its suitability for comprehensive assessments in dynamic ecological scenarios.Keywords: Wet grasslands, Carbon, Nitrogen, MONICA, SPOTPY algorithm
Burned area detection based on Planet imagery using virtual SWIR band
Authors: Kim Byeongcheol , Park Seonyoung
Published: March 2024

Forest fires pose significant threats to both human safety and the natural ecosystem. Detecting and accurately estimating the extent of the burned area is crucial for effective response planning. Remote sensing emerges as a valuable solution for estimating the burned area, with various satellites employed in previous studies. Unlike these satellites, microsatellites offer a promising alternative with higher spatiotemporal resolution. In this study, we utilized PlanetScope imagery and implemented the U-Net model. PlanetScope provides images at a 3m spatial resolution and revisits the same area every day, offering a distinct advantage in accurately estimating burned areas across different scales of fire events. However, PlanetScope lacks a Shortwave Infrared (SWIR) band commonly used in forest fire studies. To address this limitation, a virtual SWIR band was introduced in this study. To enhance accuracy in specific regions, a virtual SWIR band was created using machine learning techniques using the SWIR images from Landsat and Sentinel-2. Our approaches were tested in four study regions. The U-Net model was employed to generate burned area prediction maps, and each model's performance was evaluated using several metrics, including intersection-over-union (IoU), mean IoU, recall, precision, F1-Score, and the Kappa coefficient. In this study, we not only validated the effectiveness of our proposed methods but also identified the potential to enhance the accuracy of burned area estimations, particularly for microsatellites lacking a SWIR band.
Downstream jets at interplanetary shocks: first observations and comparison with the magnetosheath
Authors: Hietala Heli , Trotta Domenico , Fedeli Annamaria , Wilson III Lynn B. , Vuorinen Laura , LaMoury Adrian T. , Coburn Jesse T.
Published: March 2024

Localised dynamic pressure enhancements—jets—are regularly observed downstream of the Earth’s bow shock. They drive enhanced particle acceleration, larger amplitude magnetic field variations and reconnecting current sheets. Various shock simulations have also exhibited jets, suggesting that they are not unique to the bow shock.Here, we report the first observations of jet-like structures downstream of interplanetary shocks. We introduce an analysis approach suitable for such conditions and apply it to Wind spacecraft data using tools developed in the EU-project SERPENTINE. We first demonstrate the methods on a particularly high Mach number interplanetary shock that has properties comparable to the Earth’s bow shock. To further our understanding, we also investigate two low beta, low Mach number interplanetary shocks, i.e., conditions that are rare for the bow shock.The jet-like structures we find are tens of ion inertial lengths in size, and some are observed further away from the shock than in a limited magnetosheath. We find that their properties are similar to those of magnetosheath jets: in the frame of the shock these structures are fast, cold, and most have no strong magnetic field variations. All three interplanetary shocks feature foreshock activity, but no strongly compressive waves. We discuss the implications these findings have for the proposed jet formation mechanisms. The prospects of observing downstream jets in further detail with future missions look promising.
Catchment Classification-Based Comparison of Hydrological Models to Inform Water Systems Analysis
Authors: Srivastava Saumya , Liu Leyang , Wadhwa Abhinav , Reghunath Gowri , Budamala Venkatesh , Dobson Barnaby , Kumar Dasika Nagesh , Mijic Ana
Published: March 2024

Choosing a suitable model and determining the best calibration method are complex processes. These can be simplified by comparing uncalibrated models and analyzing modeling results based on catchment characteristics. The amalgamation of these two stages forms "informing water systems analysis." This study examines the application of the Water Systems Integrated Modelling framework (WSIMOD), which is a comprehensive water systems model applied previously for catchments in the UK, and the Soil and Water Assessment Tool (SWAT), a commonly used hydrological model in India. The comparison is conducted using a catchment classification scheme based on physiography. This approach establishes a connection between the catchment characteristics and the model performances, providing valuable insights for the analysis of water systems. WSIMOD demonstrates superior performance compared to SWAT in its out-of-the-box configuration, particularly when simulating average flows. WSIMOD necessitates a greater amount of data preparation compared to SWAT, but it involves a less complex calibration process. The performance of SWAT is highly dependent on the characteristics of each catchment, necessitating the use of multi-site calibration. WSIMOD's performance is not significantly influenced by catchment characteristics, enabling regions within the same agro-ecological zone to share identical parameter values. The catchment classification analysis indicated that to enhance the accuracy of the SWAT model, it is necessary to select topography, precipitation, and soil parameters for calibration. Additionally, the infiltration rate and residence times of water should be further refined to improve the WSIMOD model. This proposed methodology facilitates and simplifies the processes of model selection and calibration.
Origin of silty basal ice in Greenland
Authors: Ardoin Lisa , Tison Jean-Louis , Bierman Paul , Blard Pierre-Henry , Dahl-Jensen Dorthe , Gkinis Vasileios , Larose Catherine , Steffensen Jorge Peder , Rockmann Thomas , Fripiat François
Published: March 2024

Stratigraphically disturbed and debris-rich, the basal silty layers of Greenland ice sheet bear unique information on the environment prior to the ice sheet build up [1] and on the subglacial ecosystem [2]. Previous studies have shown that processes such as mixing, diffusion, melting and refreezing, gas expulsion, and in-situ production of CO2 and CH4 have disturbed the paleoclimatic signals within the ice silty layers of Greenland [2, 3, 4]. Analytical techniques commonly used in deep ice core studies encounter limitations when applied to the ice-bedrock interface layers due to embedded debris. As part of the DEEPICE project, we have revisited the paleoclimatic information preserved within the basal layers of Greenland updating gases measurement techniques suitable for analysing silty ice. We analysed the gas composition (N2, O2, Ar, CO2, CH4, N2O) of samples retrieved from the basal ice and underneath sediments of Camp Century (new data set) and from the basal ice of GRIP (new data set for N2O and improving previous resolution for other gases species). Our results show a large accumulation of greenhouse gases (up to 12% and 3% of CO2 and CH4) associated with O2 depletion (down to 5%), a relative accumulation of Ar (up to 1.5%) and a total gas loss (down to 5mL of gas per kg) within the last meters of ice above the bedrock. As the greenhouse gases probably have a biological origin, we performed genomic sequencing at different locations of the silty sequence to determine whether the genes required for potential biogeochemical cycling were present and whether they differed with depth. Differences are reported between Camp Century and GRIP.  In the light of these new measurements, we will discuss the processes at play in the silty layers. [1] Christ et al., 2021, Proc. Nat. Acad. Sci. [2] Souchez et al., 2006, Geophys. Res. Lett., 33, L24503.[3] Verbeke et al., 2002, Annals of Glaciology 35, 231-236. [4] Goossens et al., 2016, The Cryosphere, 10(2), 553-567.
Spatial-Temporal Analysis of Forest Mortality
Authors: Alibakhshi Sara
Published: March 2024

Climate-induced forest mortality poses an increasing threat worldwide, which calls for developing robust approaches to generate early warning signals of upcoming forest state change. This research explores the potential of satellite imagery, utilizing advanced spatio-temporal indicators and methodologies, to assess the state of forests preceding mortality events. Traditional approaches, such as techniques based on temporal analyses, are impacted by limitations related to window size selection and detrending methods, potentially leading to false alarms. To tackle these challenges, our study introduces two new approaches, namely the Spatial-Temporal Moran (STM) and Spatial-Temporal Geary (STG) approaches, both focusing on local spatial autocorrelation measures. These approaches can effectively address the shortcomings inherent in traditional methods. The research findings were assessed across three study sites within California national parks, and Kendall's tau was employed to quantify the significance of false and positive alarms. To facilitate the measurement of ecosystem state change, trend estimation, and identification of early warning signals, this study also provides "stew" R package. The implications of this research extend to various groups, such as ecologists, conservation practitioners, and policymakers, providing them with the means to address emerging environmental challenges in global forest ecosystems.
Mapping internal stress field in deforming rocks using synchrotron high-energy X-ray diffraction
Authors: Jacob Jean-baptiste , Cordonnier Benoît , Wright Jonathan , Renard François
Published: March 2024

Understanding the mechanisms controlling brittle rock failure at the grain to sub-grain scale is a fundamental challenge in geosciences. Recent advances in triaxial compression and dynamic shock experiments combined with dynamic X-ray microtomography provide unparalleled insights into the 3D strain field evolution within deforming rocks. However, these methods do not accurately predict the heterogeneous internal stress field prior to failure, which is crucial for predicting microfracture initiation and propagation, leading to macroscopic failure. In the past decade, efforts have focused on developing synchrotron X-ray diffraction techniques leveraging the high penetrative capacity of hard X-rays from the last generations of synchrotron light sources. These techniques offer spatially resolved information on crystal phase orientation and elastic strain within a 3D volume. The local orientation and elastic strain tensor is reconstructed grain-by-grain, with precision down to approximately 10-3 radian for orientation and 10-4 for strain. Stress is then calculated using Hooke's law for anisotropic materials and the elastic constants of the crystal phases. We employed 3D X-ray diffraction to investigate the internal stress field evolution in a rock core sample deformed under triaxial compression in the Hades apparatus. A 5mm-diameter core of Berea sandstone was subjected to axial step loading under constant radial stress of 10 MPa, reaching brittle failure at around 90 MPa differential stress. Elastic strain of individual quartz grains were measured at different load steps, and elastic stresses were calculated, providing maps of the internal strain and stress field in the sample. Results reveal progressive elastic shortening of quartz grains parallel to the compression axis and elongation in orthogonal directions due to the Poisson’s effect. Reorientation of principal stress components is also observed with increasing axial stress, which tend to align with the macroscopic stress field. Internal stresses distribution varies within a range of ca. 300 MPa, suggesting local stress amplifications occurred interpreted as force chains, potentially favoring crack nucleation. This experiment is among the first ones to characterize in-situ the stress distribution in a natural rock under compressive loading, and demonstrates the potential of synchrotron diffraction techniques for investigating strain and stress in geological materials.